IB/hns: Fix the bug when free mr

If the resources of mr are freed while executing the user case, hardware
can not been notified in hip06 SoC. Then hardware will hold on when it
reads the payload by the PA which has been released.

In order to slove this problem, RoCE driver creates 8 reserved loopback
QPs to ensure zero wqe when free mr. When the mac address is reset, in
order to avoid loopback failure, we need to release the reserved loopback
QPs and recreate them.

Signed-off-by: Shaobo Xu <xushaobo2@huawei.com>
Reviewed-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>