crypto: hash - Export shash through hash

This patch allows shash algorithms to be used through the old hash
interface.  This is a transitional measure so we can convert the
underlying algorithms to shash before converting the users across.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/authenc.c b/crypto/authenc.c
index fd9f06c..40b6e9e 100644
--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -11,6 +11,7 @@
  */
 
 #include <crypto/aead.h>
+#include <crypto/internal/hash.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/authenc.h>
 #include <crypto/scatterwalk.h>
@@ -431,6 +432,8 @@
 	inst->alg.cra_aead.ivsize = enc->cra_ablkcipher.ivsize;
 	inst->alg.cra_aead.maxauthsize = auth->cra_type == &crypto_hash_type ?
 					 auth->cra_hash.digestsize :
+					 auth->cra_type ?
+					 __crypto_shash_alg(auth)->digestsize :
 					 auth->cra_digest.dia_digestsize;
 
 	inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx);