crypto: api - Introduce notifier for new crypto algorithms

Introduce a facility that can be used to receive a notification
callback when a new algorithm becomes available. This can be used by
existing crypto registrations to trigger a switch from a software-only
algorithm to a hardware-accelerated version.

A new CRYPTO_MSG_ALG_LOADED state is introduced to the existing crypto
notification chain, and the register/unregister functions are exported
so they can be called by subsystems outside of crypto.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/algboss.c b/crypto/algboss.c
index 5e6df2a..527b44d 100644
--- a/crypto/algboss.c
+++ b/crypto/algboss.c
@@ -274,6 +274,8 @@ static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
 		return cryptomgr_schedule_probe(data);
 	case CRYPTO_MSG_ALG_REGISTER:
 		return cryptomgr_schedule_test(data);
+	case CRYPTO_MSG_ALG_LOADED:
+		break;
 	}
 
 	return NOTIFY_DONE;