ah: Add struct crypto_ahash to ah_data

To support for ahash algorithms, we add a pointer to a
crypto_ahash to ah_data.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ah.h

@@ -14,6 +14,7 @@ struct ah_data
 	int			icv_trunc_len;
 
 	struct crypto_hash	*tfm;
+	struct crypto_ahash	*ahash;
 };
 
 static inline int ah_mac_digest(struct ah_data *ahp, struct sk_buff *skb,