[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/netrom/af_netrom.c b/net/netrom/af_netrom.c
index a54e7ef..8d0f30a 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -878,7 +878,7 @@
 	if (frametype == NR_PROTOEXT &&
 	    circuit_index == NR_PROTO_IP && circuit_id == NR_PROTO_IP) {
 		skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
-		skb->h.raw = skb->data;
+		skb_reset_transport_header(skb);
 
 		return nr_rx_ip(skb, dev);
 	}
@@ -904,7 +904,7 @@
 	}
 
 	if (sk != NULL) {
-		skb->h.raw = skb->data;
+		skb_reset_transport_header(skb);
 
 		if (frametype == NR_CONNACK && skb->len == 22)
 			nr_sk(sk)->bpqext = 1;
@@ -1149,7 +1149,7 @@
 		return er;
 	}
 
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 	copied     = skb->len;
 
 	if (copied > size) {