crypto: shash - Add shash_attr_alg2 helper

This patch adds the helper shash_attr_alg2 which locates a shash
algorithm based on the information in the given attribute.

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

include/crypto/internal/hash.h

@@ -60,6 +60,8 @@ int crypto_init_shash_spawn(struct crypto_shash_spawn *spawn,
 			    struct shash_alg *alg,
 			    struct crypto_instance *inst);
 
+struct shash_alg *shash_attr_alg(struct rtattr *rta, u32 type, u32 mask);
+
 static inline void *crypto_ahash_ctx(struct crypto_ahash *tfm)
 {
 	return crypto_tfm_ctx(&tfm->base);