zstd: Backport fix for SIGBUS on armv6 from zstd 1.5.0

Backport zstd commit `28d0120b` (Avoid SIGBUS on armv6, 2021-05-11,
`v1.5.0^2~11^2`) to our bundled copy of zstd 1.4.5.

Fixes: #22754
diff --git a/Utilities/cmzstd/lib/common/mem.h b/Utilities/cmzstd/lib/common/mem.h
index 89c8aea..c3f98fc 100644
--- a/Utilities/cmzstd/lib/common/mem.h
+++ b/Utilities/cmzstd/lib/common/mem.h
@@ -173,9 +173,7 @@
  * Prefer these methods in priority order (0 > 1 > 2)
  */
 #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
-#  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
-#    define MEM_FORCE_MEMORY_ACCESS 2
-#  elif defined(__INTEL_COMPILER) || defined(__GNUC__) || defined(__ICCARM__)
+#  if defined(__INTEL_COMPILER) || defined(__GNUC__) || defined(__ICCARM__)
 #    define MEM_FORCE_MEMORY_ACCESS 1
 #  endif
 #endif
diff --git a/Utilities/cmzstd/lib/common/xxhash.c b/Utilities/cmzstd/lib/common/xxhash.c
index 597de18..3d7655e 100644
--- a/Utilities/cmzstd/lib/common/xxhash.c
+++ b/Utilities/cmzstd/lib/common/xxhash.c
@@ -30,9 +30,7 @@
  * Prefer these methods in priority order (0 > 1 > 2)
  */
 #ifndef XXH_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
-#  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
-#    define XXH_FORCE_MEMORY_ACCESS 2
-#  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
+#  if (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) )) || \
   defined(__ICCARM__)
 #    define XXH_FORCE_MEMORY_ACCESS 1