RDMA/hns: Add command queue support for hip08 RoCE driver

The command queue is the configuration queue. The software
configures hardware by filling the commands into command
queues. It includes command send queue and receive queue.

In hip08 RoCE engine, It supports to configure and query
registers by command queue.

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>