crypto: s390 - add System z hardware support for GHASH

This patch adds System z hardware acceleration support for the GHASH
algorithm for GCM (Galois/Counter Mode).
The hardware support is available beginning with System z196.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/s390/crypto/crypt_s390.h

@@ -91,6 +91,7 @@ enum crypt_s390_kimd_func {
 	KIMD_SHA_1   = CRYPT_S390_KIMD | 1,
 	KIMD_SHA_256 = CRYPT_S390_KIMD | 2,
 	KIMD_SHA_512 = CRYPT_S390_KIMD | 3,
+	KIMD_GHASH   = CRYPT_S390_KIMD | 65,
 };
 
 /*