zstd: Backport fix for SIGBUS on armv6 from zstd 1.5.0
Backport zstd PR 2633 to our bundled copy of zstd 1.4.5.
This is for the CMake 3.20 and 3.21 release branches. !6622 (merged) already updated to zstd 1.5.0 for CMake 3.22 and later.
Fixes: #22754 (closed)