[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/net/ieee80211/ieee80211_tx.c b/net/ieee80211/ieee80211_tx.c
index 3fca434..62a8a2b 100644
--- a/net/ieee80211/ieee80211_tx.c
+++ b/net/ieee80211/ieee80211_tx.c
@@ -228,7 +228,7 @@
 	if (eth->h_proto != htons(ETH_P_IP))
 		return 0;
 
-	ip = skb->nh.iph;
+	ip = ip_hdr(skb);
 	switch (ip->tos & 0xfc) {
 	case 0x20:
 		return 2;