net: smsc: epic100: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles

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

drivers/net/ethernet/smsc/epic100.c

@@ -1037,7 +1037,7 @@ static void epic_tx(struct net_device *dev, struct epic_private *ep)
 		skb = ep->tx_skbuff[entry];
 		pci_unmap_single(ep->pci_dev, ep->tx_ring[entry].bufaddr,
 				 skb->len, PCI_DMA_TODEVICE);
-		dev_kfree_skb_irq(skb);
+		dev_consume_skb_irq(skb);
 		ep->tx_skbuff[entry] = NULL;
 	}