RDMA/hns: Optimize 0 hop addressing for EQE buffer

Use the new mtr interface to simple the hop 0 addressing and multihop
addressing process.

Link: https://lore.kernel.org/r/1586779091-51410-4-git-send-email-liweihang@huawei.com


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