RDMA/hw/hns/hns_roce_mr: Add missing description for 'hr_dev' param

Fixes the following W=1 kernel build warning(s):

 drivers/infiniband/hw/hns/hns_roce_mr.c:1003: warning: Function parameter or member 'hr_dev' not described in 'hns_roce_mtr_create'

Link: https://lore.kernel.org/r/20210121094519.2044049-6-lee.jones@linaro.org
Cc: Lijun Ou <oulijun@huawei.com>
Cc: Weihang Li <liweihang@huawei.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hns/hns_roce_mr.c

@@ -990,6 +990,7 @@ static int mtr_init_buf_cfg(struct hns_roce_dev *hr_dev,
 /**
  * hns_roce_mtr_create - Create hns memory translate region.
  *
+ * @hr_dev: RoCE device struct pointer
  * @mtr: memory translate region
  * @buf_attr: buffer attribute for creating mtr
  * @ba_page_shift: page shift for multi-hop base address table