gianfar: Fix kfree(skb)

Noticed by Li Yang.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index a7a6737..44cbf26 100644
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -1317,7 +1317,7 @@
 		skb_new = skb_realloc_headroom(skb, GMAC_FCB_LEN);
 		if (!skb_new) {
 			dev->stats.tx_errors++;
-			kfree(skb);
+			kfree_skb(skb);
 			return NETDEV_TX_OK;
 		}
 		kfree_skb(skb);