[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>
diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index 934f259..137341b 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -1275,7 +1275,7 @@
 	skb->protocol = htons(ETH_P_IP);
 	skb_pull(skb, 13);
 	skb->dev   = dev;
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 
 	stats = dev->priv;
 	stats->rx_packets++;
@@ -1522,7 +1522,7 @@
 		/* Non routable, so force a drop if we slip up later */
 		ddp->deh_len_hops = htons(skb->len + (DDP_MAXHOPS << 10));
 	}
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 
 	return atalk_rcv(skb, dev, pt, orig_dev);
 freeit: