RDMA/hns: Fix UAF for cq async event

The refcount of CQ is not protected by locks. When CQ asynchronous
events and CQ destruction are concurrent, CQ may have been released,
which will cause UAF.

Use the xa_lock() to protect the CQ refcount.

Fixes: 9a443537

 ("IB/hns: Add driver files for hns RoCE driver")
Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://lore.kernel.org/r/20240412091616.370789-6-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>