crypto: sa2ul - Add AEAD algorithm support

Add support for sa2ul hardware AEAD for hmac(sha256),cbc(aes) and
hmac(sha1),cbc(aes) algorithms.
Signed-off-by: Keerthy <j-keerthy@ti.com>
[t-kristo@ti.com: number of bug fixes, major refactoring and cleanup of
 code]
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/sa2ul.h

@@ -313,6 +313,7 @@ struct sa_tfm_ctx {
 	union {
 		struct crypto_sync_skcipher	*skcipher;
 		struct crypto_ahash		*ahash;
+		struct crypto_aead		*aead;
 	} fallback;
 };