[bmi2] Add lzcnt and bmi target attributes

* When dynamic dispatching to bmi2 add lzcnt and bmi to the
  TARGET_ATTRIBUTE.
* Centralize the bmi2 TARGET_ATTRIBUTE definition to
  BMI2_TARGET_ATTRIBUTE so we can change it in the future.
* Only enable bmi2 when both bmi1 & bmi2 are supported. There shouldn't
  be any cases where bmi2 is supported but bmi1 isn't. But, since we are
  using the instruction we should check bmi1 as well.

lib/decompress/zstd_decompress.c

@@ -56,7 +56,6 @@
 *  Dependencies
 *********************************************************/
 #include "../common/zstd_deps.h"   /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */
-#include "../common/cpu.h"         /* bmi2 */
 #include "../common/mem.h"         /* low level memory routines */
 #define FSE_STATIC_LINKING_ONLY
 #include "../common/fse.h"
@@ -265,7 +264,7 @@ static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx)
     dctx->noForwardProgress = 0;
     dctx->oversizedDuration = 0;
 #if DYNAMIC_BMI2
-    dctx->bmi2 = ZSTD_cpuid_bmi2(ZSTD_cpuid());
+    dctx->bmi2 = ZSTD_cpuSupportsBmi2();
 #endif
     dctx->ddictSet = NULL;
     ZSTD_DCtx_resetParameters(dctx);