[SK_BUFF]: Introduce ip_hdr(), remove skb->nh.iph

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 51e994f..a37bb20 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -1428,7 +1428,7 @@
 		tcpsum |= offset + skb->csum_offset;	/* sum write */
 
 		ctrl = CALSUM | WR_SUM | INIT_SUM | LOCK_SUM;
-		if (skb->nh.iph->protocol == IPPROTO_UDP)
+		if (ip_hdr(skb)->protocol == IPPROTO_UDP)
 			ctrl |= UDPTCP;
 
 		if (tcpsum != sky2->tx_tcpsum) {