net-next/hinic: fix a problem in hinic_xmit_frame()

The calculation of "wqe_size" is not correct when the tx queue is busy in
hinic_xmit_frame().

When there are no free WQEs, the tx flow will unmap the skb buffer, then
ring the doobell for the pending packets. But the "wqe_size" which used
to calculate the doorbell address is not correct. The wqe size should be
cleared to 0, otherwise, it will cause a doorbell error.

This patch fixes the problem.
Reported-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Zhao Chen <zhaochen6@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/huawei/hinic/hinic_tx.c

@@ -229,6 +229,7 @@ netdev_tx_t hinic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
 		txq->txq_stats.tx_busy++;
 		u64_stats_update_end(&txq->txq_stats.syncp);
 		err = NETDEV_TX_BUSY;
+		wqe_size = 0;
 		goto flush_skbs;
 	}