RDMA/hns: Modify LSN init value

driver inclusion
category: bugfix
bugzilla: NA
CVE: NA

Send io constructs a scenario where rq wqe is
insufficient. The performance of 1620 is to
resend all messages and does not satisfy the
limit wqe scenario.

Feature or Bugfix: Bugfix

Signed-off-by: wangsirong <wangsirong@huawei.com>
Signed-off-by: liyangyang (M) <liyangyang20@huawei.com>
Reviewed-by: liuyixian <liuyixian@huawei.com>
Reviewed-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>