[SK_BUFF]: Introduce skb_network_offset()

For the quite common 'skb->nh.raw - skb->data' sequence.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index 587123c..d24914d 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -323,7 +323,7 @@
 			nores = 1;
 			break;
 		}
-		__skb_pull(skb, skb->nh.raw - skb->data);
+		__skb_pull(skb, skb_network_offset(skb));
 	} while ((q = NEXT_SLAVE(q)) != start);
 
 	if (nores && skb_res == NULL) {