RDMA/hns: Add memory barrier when writing hw

driver inclusion
category: bugfix
bugzilla: NA
CVE: NA

It is the right way to add memory barrier when writing hw.

Feature or Bugfix:Bugfix
Signed-off-by: Nliyangyang (M) <liyangyang20@huawei.com>
Reviewed-by: Noulijun <oulijun@huawei.com>
Reviewed-by: Nliuyixian <liuyixian@huawei.com>
Reviewed-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -1090,6 +1090,9 @@ static int __hns_roce_cmq_send(struct hns_roce_dev *hr_dev,
 		handle++;
 	}
 
+	/* Memory barrier */
+	wmb();
+
 	/* Write to hardware */
 	roce_write(hr_dev, ROCEE_TX_CMQ_TAIL_REG, csq->next_to_use);