RDMA/hns: Add support for processing send wr and receive wr

This patch is implementing for posting send request and
receiving request for hip08 RoCE driver. such as
post send verbs and post recv verbs.

Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Shaobo Xu <xushaobo2@huawei.com>
Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>