crypto: powerpc - CRYPT_CRC32C_VPMSUM should depend on ALTIVEC

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: 6dd7a82 ("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>

crypto/Kconfig

@@ -439,7 +439,7 @@ config CRYPTO_CRC32C_INTEL
 
 config CRYPT_CRC32C_VPMSUM
 	tristate "CRC32c CRC algorithm (powerpc64)"
-	depends on PPC64
+	depends on PPC64 && ALTIVEC
 	select CRYPTO_HASH
 	select CRC32
 	help