The optimised crc32c implementation depends on VMX (aka. Altivec)
instructions, so the kernel must be built with Altivec support in order
for the crc32c code to build.

Fixes: 6dd7a82c ("crypto: powerpc - Add POWER8 optimised crc32c")
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>