RDMA/hns: Simplify function's resource related command

Use hr_reg_write/read() to simplify codes about configuring function's
resource. And because the design of PF/VF fields is same, they can be
defined only once.

Link: https://lore.kernel.org/r/1617715514-29039-2-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@nvidia.com>