crypto: crc32c - Add ahash implementation

This patch reimplements crc32c using the ahash interface.  This
allows one tfm to be used by an unlimited number of users provided
that they all use the same key (which all current crc32c users do).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/Kconfig

@@ -213,7 +213,7 @@ comment "Digest"
 
 config CRYPTO_CRC32C
 	tristate "CRC32c CRC algorithm"
-	select CRYPTO_ALGAPI
+	select CRYPTO_HASH
 	select LIBCRC32C
 	help
 	  Castagnoli, et al Cyclic Redundancy-Check Algorithm.  Used