[SK_BUFF]: Introduce skb_reset_transport_header(skb)

For the common, open coded 'skb->h.raw = skb->data' operation, so that we can
later turn skb->h.raw into a offset, reducing the size of struct sk_buff in
64bit land while possibly keeping it as a pointer on 32bit.

This one touches just the most simple cases:

skb->h.raw = skb->data;
skb->h.raw = {skb_push|[__]skb_pull}()

The next ones will handle the slightly more "complex" cases.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/cxgb3/sge.c

@@ -1622,7 +1622,7 @@ static inline int rx_offload(struct t3cdev *tdev, struct sge_rspq *rq,
 	rq->offload_pkts++;
 	skb_reset_mac_header(skb);
 	skb_reset_network_header(skb);
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 
 	if (rq->polling) {
 		rx_gather[gather_idx++] = skb;