RDMA/hns: Set reset flag when hw resetting

When hw resetting, there is no response from hw when driver sending cmdq.
If driver still send cmdq to hw, the reset process may be blocked.  So
reset flag should be set to intercept the cmdq command when driver
receiving "notify down" signal.

Signed-off-by: Lang Cheng <chenglang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>