s390/pkey_pckmo: Return with success for valid protected key types

The key_to_protkey handler function in module pkey_pckmo should return
with success on all known protected key types, including the new types
introduced by fd197556eef5 ("s390/pkey: Add AES xts and HMAC clear key
token support").

Fixes: fd197556eef5 ("s390/pkey: Add AES xts and HMAC clear key token support")
Signed-off-by: Holger Dengler <[e-mail]>
Reviewed-by: Ingo Franzki <[e-mail]>
Signed-off-by: Heiko Carstens <[e-mail]>

drivers/s390/crypto/pkey_pckmo.c

···
 		memcpy(protkey, t->protkey, t->len);
 		*protkeylen = t->len;
 		*protkeytype = t->keytype;
+		rc = 0;
 		break;
 	}
 	case TOKVER_CLEAR_KEY: {