[SK_BUFF]: Introduce skb_mac_header()

For the places where we need a pointer to the mac header, it is still legal to
touch skb->mac.raw directly if just adding to, subtracting from or setting it
to another layer header.

This one also converts some more cases to skb_reset_mac_header() that my
regex missed as it had no spaces before nor after '=', ugh.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/802/hippi.c b/net/802/hippi.c
index d871900..87ffc12 100644
--- a/net/802/hippi.c
+++ b/net/802/hippi.c
@@ -132,7 +132,7 @@
 	 */
 	skb->dev = dev;
 	skb_reset_mac_header(skb);
-	hip = (struct hippi_hdr *)skb->mac.raw;
+	hip = (struct hippi_hdr *)skb_mac_header(skb);
 	skb_pull(skb, HIPPI_HLEN);
 
 	/*