RDMA/hns: Optimize the MR registration process

When creating or re-registering an MR, storing the PDN, access flag and
IOVA information ASAP can simplify the number of parameters passed into
the subsequent process.

Link: https://lore.kernel.org/r/1611395282-991-3-git-send-email-liweihang@huawei.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Lang Cheng <chenglang@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>