Rename zstd_(de)compress.c to (de)compress.c

contrib/linux-kernel/lib/zstd/Makefile

@@ -4,6 +4,6 @@ obj-$(CONFIG_ZSTD_DECOMPRESS) += zstd_decompress.o
 ccflags-y += -O3
 
 zstd_compress-y := entropy_common.o fse_decompress.o xxhash.o zstd_common.o \
-				fse_compress.o huf_compress.o zstd_compress.o
+				fse_compress.o huf_compress.o compress.o
 zstd_decompress-y := entropy_common.o fse_decompress.o xxhash.o zstd_common.o \
-				huf_decompress.o zstd_decompress.o
+				huf_decompress.o decompress.o