qede: remove some unused code in function qede_selftest_receive_traffic

Remove set but not used variables 'sw_comp_cons' and 'hw_comp_cons'
to fix gcc '-Wunused-but-set-variable' warning:

drivers/net/ethernet/qlogic/qede/qede_ethtool.c: In function qede_selftest_receive_traffic:
drivers/net/ethernet/qlogic/qede/qede_ethtool.c:1569:20:
 warning: variable sw_comp_cons set but not used [-Wunused-but-set-variable]
drivers/net/ethernet/qlogic/qede/qede_ethtool.c: In function qede_selftest_receive_traffic:
drivers/net/ethernet/qlogic/qede/qede_ethtool.c:1569:6:
 warning: variable hw_comp_cons set but not used [-Wunused-but-set-variable]

After removing 'hw_comp_cons',the memory barrier 'rmb()' and its comments become useless,
so remove them as well.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qede/qede_ethtool.c

@@ -1566,7 +1566,7 @@ static int qede_selftest_transmit_traffic(struct qede_dev *edev,
 
 static int qede_selftest_receive_traffic(struct qede_dev *edev)
 {
-	u16 hw_comp_cons, sw_comp_cons, sw_rx_index, len;
+	u16 sw_rx_index, len;
 	struct eth_fast_path_rx_reg_cqe *fp_cqe;
 	struct qede_rx_queue *rxq = NULL;
 	struct sw_rx_data *sw_rx_data;
@@ -1596,17 +1596,6 @@ static int qede_selftest_receive_traffic(struct qede_dev *edev)
 			continue;
 		}
 
-		hw_comp_cons = le16_to_cpu(*rxq->hw_cons_ptr);
-		sw_comp_cons = qed_chain_get_cons_idx(&rxq->rx_comp_ring);
-
-		/* Memory barrier to prevent the CPU from doing speculative
-		 * reads of CQE/BD before reading hw_comp_cons. If the CQE is
-		 * read before it is written by FW, then FW writes CQE and SB,
-		 * and then the CPU reads the hw_comp_cons, it will use an old
-		 * CQE.
-		 */
-		rmb();
-
 		/* Get the CQE from the completion ring */
 		cqe = (union eth_rx_cqe *)qed_chain_consume(&rxq->rx_comp_ring);