RDMA/hns: Avoid filling sgid index when modifying QP to RTR

RDMA/hns: Avoid filling sgid index when modifying QP to RTR

ULP usually set IB(V)_QP_AV when trying to modify QP to RTR if they want
to record sgid index into QPC. For UD QPs, it is useless because it will
be included in WQE. For RC QPs, it will be filled in
hns_roce_set_path(). So sgid index shouldn't be filled by default. Then
hns_get_gid_index() is moved to hns_roce_hw_v1.c because it is only called
in it.

Fixes: 926a01dc000d ("RDMA/hns: Add QP operations support for hip08 SoC")
Link: https://lore.kernel.org/r/1612517974-31867-2-git-send-email-liweihang@huawei.com
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>