module: resync part of Makefile.bsd

sha256-armv8.S and sha512-armv8.S need the same treatment as the sse
bits; removal of -mgeneral-regs-only from flags.

This fixes errors about requiring NEON, which is a difference in clang
vs. gcc treatment of -mgeneral-regs-only being specified on asm files.

Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>
Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
Closes #14715