net: ixp4xx_eth: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles

dev_consume_skb_irq() should be called in eth_txdone_irq() 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/xscale/ixp4xx_eth.c

@@ -139,7 +139,7 @@
 #ifdef __ARMEB__
 typedef struct sk_buff buffer_t;
 #define free_buffer dev_kfree_skb
-#define free_buffer_irq dev_kfree_skb_irq
+#define free_buffer_irq dev_consume_skb_irq
 #else
 typedef void buffer_t;
 #define free_buffer kfree