RDMA/hns: Move priv in order to add multiple hns_roce support

Move the data member called priv from hns_roce_hw to hns_roce_dev
structure in order to support multiple hns_roce devices in one
system at the same time. For example, there are two hip06 engines
in the system.

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>