[SK_BUFF]: Introduce arp_hdr(), remove skb->nh.arph

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 01d0e8d..7110779 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -721,7 +721,7 @@
 	if (in_dev == NULL)
 		goto out;
 
-	arp = skb->nh.arph;
+	arp = arp_hdr(skb);
 
 	switch (dev_type) {
 	default:
@@ -937,7 +937,7 @@
 				 (2 * sizeof(u32)))))
 		goto freeskb;
 
-	arp = skb->nh.arph;
+	arp = arp_hdr(skb);
 	if (arp->ar_hln != dev->addr_len ||
 	    dev->flags & IFF_NOARP ||
 	    skb->pkt_type == PACKET_OTHERHOST ||