crypto: crc32c-vpmsum - Convert to CPU feature based module autoloading

This patch utilises the GENERIC_CPU_AUTOPROBE infrastructure
to automatically load the crc32c-vpmsum module if the CPU supports
it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>