[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_route.c b/net/rose/rose_route.c
index a1233e1..1f9aefd 100644
--- a/net/rose/rose_route.c
+++ b/net/rose/rose_route.c
@@ -906,7 +906,7 @@
 			}
 		}
 		else {
-			skb->h.raw = skb->data;
+			skb_reset_transport_header(skb);
 			res = rose_process_rx_frame(sk, skb);
 			goto out;
 		}