[copyright][license] Switch to yearless copyright and some cleanup in the linux-kernel files

* Switch to yearless copyright per FB policy
* Fix up SPDX-License-Identifier lines in `contrib/linux-kernel` sources
* Add zstd copyright/license header to the `contrib/linux-kernel` sources
* Update the `tests/test-license.py` to check for yearless copyright
* Improvements to `tests/test-license.py`
* Check `contrib/linux-kernel` in `tests/test-license.py`

lib/compress/fse_compress.c

@@ -1,6 +1,6 @@
 /* ******************************************************************
  * FSE : Finite State Entropy encoder
- * Copyright (c) 2013-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  *
  *  You can contact the author at :
  *  - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy

lib/compress/hist.c

@@ -1,7 +1,7 @@
 /* ******************************************************************
  * hist : Histogram functions
  * part of Finite State Entropy project
- * Copyright (c) 2013-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  *
  *  You can contact the author at :
  *  - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy

lib/compress/hist.h

@@ -1,7 +1,7 @@
 /* ******************************************************************
  * hist : Histogram functions
  * part of Finite State Entropy project
- * Copyright (c) 2013-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  *
  *  You can contact the author at :
  *  - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy

lib/compress/huf_compress.c

@@ -1,6 +1,6 @@
 /* ******************************************************************
  * Huffman encoder, part of New Generation Entropy library
- * Copyright (c) 2013-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  *
  *  You can contact the author at :
  *  - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy

lib/compress/zstd_compress.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_compress_internal.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_compress_literals.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_compress_literals.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_compress_sequences.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_compress_sequences.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_compress_superblock.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_compress_superblock.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_cwksp.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_double_fast.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_double_fast.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_fast.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_fast.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_lazy.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_lazy.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_ldm.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_ldm.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_ldm_geartab.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_opt.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
+ * Copyright (c) Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstd_opt.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstdmt_compress.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the

lib/compress/zstdmt_compress.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2021, Yann Collet, Facebook, Inc.
+ * Copyright (c) Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the