crypto: x86/cast6-avx - convert to skcipher interface

Convert the AVX implementation of CAST6 from the (deprecated) ablkcipher
and blkcipher interfaces over to the skcipher interface.  Note that this
includes replacing the use of ablk_helper with crypto_simd.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/Kconfig

@@ -1260,12 +1260,11 @@ config CRYPTO_CAST6
 config CRYPTO_CAST6_AVX_X86_64
 	tristate "CAST6 (CAST-256) cipher algorithm (x86_64/AVX)"
 	depends on X86 && 64BIT
-	select CRYPTO_ALGAPI
-	select CRYPTO_CRYPTD
-	select CRYPTO_ABLK_HELPER
-	select CRYPTO_GLUE_HELPER_X86
-	select CRYPTO_CAST_COMMON
+	select CRYPTO_BLKCIPHER
 	select CRYPTO_CAST6
+	select CRYPTO_CAST_COMMON
+	select CRYPTO_GLUE_HELPER_X86
+	select CRYPTO_SIMD
 	select CRYPTO_XTS
 	help
 	  The CAST6 encryption algorithm (synonymous with CAST-256) is