liblzma: Speed up CRC32 calculation on 64-bit LoongArch
The crc.w.{b/h/w/d}.w instructions in LoongArch can calculate the CRC32
result for 1/2/4/8 bytes in a single operation. Using these is much
faster compared to the generic method.
Optimized CRC32 is enabled unconditionally on 64-bit LoongArch because
the LoongArch specification says that CRC32 instructions shall be
implemented for 64-bit processors. Optimized CRC32 isn't enabled for
32-bit LoongArch processors because not enough information is available
about them.
Co-authored-by: Lasse Collin <lasse.collin@tukaani.org> Closes: https://github.com/tukaani-project/xz/pull/86