crypto: hisilicon/qm - Add the default processing branch

The cmd type can be extended. Currently, only four types of cmd
can be processed. Therefor, add the default processing branch
to intercept incorrect parameter input.
Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/hisilicon/qm.c

@@ -645,6 +645,9 @@ int qm_set_and_get_xqc(struct hisi_qm *qm, u8 cmd, void *xqc, u32 qp_id, bool op
 		tmp_xqc = qm->xqc_buf.aeqc;
 		xqc_dma = qm->xqc_buf.aeqc_dma;
 		break;
+	default:
+		dev_err(&qm->pdev->dev, "unknown mailbox cmd %u\n", cmd);
+		return -EINVAL;
 	}
 
 	/* Setting xqc will fail if master OOO is blocked. */