RDMA/hns: Update assignment method for owner field of send wqe

When posting a work reqeust, it need to update the owner bit of send
wqe. This patch mainly fix the bug when posting multiply work
request.

Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>