KEYS: Fix stale key registration at error path

When loading encrypted-keys module, if the last check of
aes_get_sizes() in init_encrypted() fails, the driver just returns an
error without unregistering its key type. This results in the stale
entry in the list. In addition to memory leaks, this leads to a kernel
crash when registering a new key type later.

This patch fixes the problem by swapping the calls of aes_get_sizes()
and register_key_type(), and releasing resources properly at the error
paths.

Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=908163
Cc: <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>
Signed-off-by: Mimi Zohar <[e-mail]>

security/keys/encrypted-keys/encrypted.c

···
 	ret = encrypted_shash_alloc();
 	if (ret < 0)
 		return ret;
+	ret = aes_get_sizes();
+	if (ret < 0)
+		goto out;
 	ret = register_key_type(&key_type_encrypted);
 	if (ret < 0)
 		goto out;
-	return aes_get_sizes();
+	return 0;
 out:
 	encrypted_shash_release();
 	return ret;