net: 8139cp: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles

dev_consume_skb_irq() should be called in cp_tx() when skb xmit
done. It makes drop profiles(dropwatch, perf) more friendly.
Signed-off-by: Yang Wei <yang.wei9@zte.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/8139cp.c

@@ -691,7 +691,7 @@ static void cp_tx (struct cp_private *cp)
 			}
 			bytes_compl += skb->len;
 			pkts_compl++;
-			dev_kfree_skb_irq(skb);
+			dev_consume_skb_irq(skb);
 		}
 
 		cp->tx_skb[tx_tail] = NULL;