RDMA/hns: Fix incorrect lsn field

In RNR NAK screnario, according to the specification, when no credit is
available, only the first fragment of the send request can be sent. The
LSN(Limit Sequence Number) field should be 0 or the entire packet will be
resent.

Fixes: 926a01d ("RDMA/hns: Add QP operations support for hip08 SoC")
Link: https://lore.kernel.org/r/1629883169-2306-1-git-send-email-liangwenpeng@huawei.com
Signed-off-by: Yixing Liu <liuyixing1@huawei.com>
Signed-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -4483,9 +4483,6 @@ static int modify_qp_rtr_to_rts(struct ib_qp *ibqp,
 
 	hr_reg_clear(qpc_mask, QPC_CHECK_FLG);
 
-	hr_reg_write(context, QPC_LSN, 0x100);
-	hr_reg_clear(qpc_mask, QPC_LSN);
-
 	hr_reg_clear(qpc_mask, QPC_V2_IRRL_HEAD);
 
 	return 0;