IB/hns: Add driver files for hns RoCE driver

These are the various new source code files for the Hisilicon
RoCE driver for ARM architecture.

Signed-off-by: Wei Hu <xavier.huwei@huawei.com>
Signed-off-by: Nenglong Zhao <zhaonenglong@hisilicon.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>