Do no use .cfi_negate_ra_state within the assembly on Arm64

Compiling openzfs on aarch64 with gcc-8 and gcc-9 is failing currently.
See issue #14965 for deeper context.

On platforms without pointer authentication, .cfi_negate_ra_state can be
defined to a no-op:
https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gdb/aarch64-tdep.c#l1413

I have tested this on Arm64 FreeBSD 13.2 and AlmaLinux-8.

Reviewed-by: Andrew Turner <andrew.turner4@arm.com>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes #14965
Closes #15784