RDMA/hns: return 0 rather than return a garbage status value

For the case where hr_qp->state == IB_QPS_RESET, an uninitialized
value in ret is being returned by function hns_roce_v2_query_qp.
Fix this by setting ret to 0 for this specific return condition.

Detected by CoverityScan, CID#1457203 ("Unitialized scalar variable")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>