net/macb: fix compilation warning for print_hex_dump() called with skb->mac_header

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb.c

@@ -776,7 +776,7 @@ static int gem_rx(struct macb *bp, int budget)
 		netdev_vdbg(bp->dev, "received skb of length %u, csum: %08x\n",
 			    skb->len, skb->csum);
 		print_hex_dump(KERN_DEBUG, " mac: ", DUMP_PREFIX_ADDRESS, 16, 1,
-			       skb->mac_header, 16, true);
+			       skb_mac_header(skb), 16, true);
 		print_hex_dump(KERN_DEBUG, "data: ", DUMP_PREFIX_ADDRESS, 16, 1,
 			       skb->data, 32, true);
 #endif