RDMA/hns: Support 0 hop addressing for WQE buffer

Add the zero hop addressing support by using new mtr interface for WQE
buffer and simple mtr invoking process, so WQE buffer can support hopnum
between 0 to 3.

Link: https://lore.kernel.org/r/1586779091-51410-5-git-send-email-liweihang@huawei.com


Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>