[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/drivers/net/plip.c b/drivers/net/plip.c
index 6bb085f..8754cf3 100644
--- a/drivers/net/plip.c
+++ b/drivers/net/plip.c
@@ -546,7 +546,7 @@
 	struct ethhdr *eth;
 	unsigned char *rawp;
 
-	skb->mac.raw=skb->data;
+	skb_reset_mac_header(skb);
 	skb_pull(skb,dev->hard_header_len);
 	eth = eth_hdr(skb);