[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/core/netpoll.c b/net/core/netpoll.c
index 496b062..8b22723 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -362,7 +362,7 @@
 		return;
 
 	skb_reset_network_header(skb);
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 	arp = arp_hdr(skb);
 
 	if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&