[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/rose/rose_loopback.c b/net/rose/rose_loopback.c
index 3e41bd9..cd01642 100644
--- a/net/rose/rose_loopback.c
+++ b/net/rose/rose_loopback.c
@@ -77,7 +77,7 @@
 		dest      = (rose_address *)(skb->data + 4);
 		lci_o     = 0xFFF - lci_i;
 
-		skb->h.raw = skb->data;
+		skb_reset_transport_header(skb);
 
 		sk = rose_find_socket(lci_o, &rose_loopback_neigh);
 		if (sk) {