RDMA/hns: remove set but not used variable 'dseg'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/infiniband/hw/hns/hns_roce_hw_v2.c: In function 'hns_roce_v2_post_send':
drivers/infiniband/hw/hns/hns_roce_hw_v2.c:194:35: warning:
 variable 'dseg' set but not used [-Wunused-but-set-variable]
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -191,7 +191,6 @@ static int hns_roce_v2_post_send(struct ib_qp *ibqp,
 	struct hns_roce_v2_ud_send_wqe *ud_sq_wqe;
 	struct hns_roce_v2_rc_send_wqe *rc_sq_wqe;
 	struct hns_roce_qp *qp = to_hr_qp(ibqp);
-	struct hns_roce_v2_wqe_data_seg *dseg;
 	struct device *dev = hr_dev->dev;
 	struct hns_roce_v2_db sq_db;
 	struct ib_qp_attr attr;
@@ -492,12 +491,6 @@ static int hns_roce_v2_post_send(struct ib_qp *ibqp,
 			roce_set_field(rc_sq_wqe->byte_4,
 				       V2_RC_SEND_WQE_BYTE_4_OPCODE_M,
 				       V2_RC_SEND_WQE_BYTE_4_OPCODE_S, hr_op);
-			if (wr->opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
-			    wr->opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
-				dseg =
-				  wqe - sizeof(struct hns_roce_v2_wqe_data_seg);
-			else
-				dseg = wqe;
 
 			ret = set_rwqe_data_seg(ibqp, wr, rc_sq_wqe, wqe,
 						&sge_ind, bad_wr);