arm64 lib32: change clang to allow -m32 on arm64

The FreeBSD driver support for clang tested explicitly for 32-bit
Intel, MIPS, or PowerPC targets where /usr/lib32/libcrt1.o was
present to decide whether -m32 should use /usr/lib32. At jrtc27's
suggestion, simply test for a 32-bit platform rather than adding
arm to the list. Upstreamed as
https://github.com/llvm/llvm-project/commit/3450272fc281979388bb845a9fffb59b42cc2e7e
Bump the freebsd version to force a bootstrap build. This is one
step in adding support for -m32 on arm64.

Reviewed by: jrtc27, brooks, dim
Differential Revision: https://reviews.freebsd.org/D40943