IB/hns: Fix the bug when destroy qp

IB/hns: Fix the bug when destroy qp

If send queue is still working when qp is in reset state by modify qp
in destroy qp function, hardware will hold on and don't work in hip06
SoC. In current codes, RoCE driver check hardware pointer of sending and
hardware pointer of processing to ensure that hardware has processed all
the dbs of this qp. But while the environment of wire becomes not good,
The checking time maybe too long.

In order to solve this problem, RoCE driver created a workqueue at probe
function. If there is a timeout when checking the status of qp, driver
initialize work entry and push it into the workqueue, Work function will
finish checking and release the related resources later.

Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Dongdong Huang(Donald) <hdd.huang@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>