RDMA/hns: Bugfix for the missing assignment for dip_idx

When the dgid-dip_idx mapping relationship exists, dip should be assigned.

Fixes: f91696f2 ("RDMA/hns: Support congestion control type selection according to the FW")
Link: https://lore.kernel.org/r/1629884592-23424-3-git-send-email-liangwenpeng@huawei.com


Signed-off-by: Junxian Huang <huangjunxian4@hisilicon.com>
Signed-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>