KEYS: revert encrypted key change

Commit fc7c70e0 "KEYS: struct key_preparsed_payload should have two
payload pointers" erroneously modified encrypted-keys.  This patch
reverts the change to that file.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>

security/keys/encrypted-keys/encrypted.c

@@ -811,7 +811,7 @@ static int encrypted_instantiate(struct key *key,
 		goto out;
 	}
 
-	prep->payload[0] = epayload;
+	rcu_assign_keypointer(key, epayload);
 out:
 	kfree(datablob);
 	return ret;