[SK_BUFF]: unions of just one member don't get anything done, kill them

Renaming skb->h to skb->transport_header, skb->nh to skb->network_header and
skb->mac to skb->mac_header, to match the names of the associated helpers
(skb[_[re]set]_{transport,network,mac}_header).

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 1e8827b..27fe10f 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -382,7 +382,7 @@
 	read_lock(&ipip6_lock);
 	if ((tunnel = ipip6_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) {
 		secpath_reset(skb);
-		skb->mac.raw = skb->nh.raw;
+		skb->mac_header = skb->network_header;
 		skb_reset_network_header(skb);
 		IPCB(skb)->flags = 0;
 		skb->protocol = htons(ETH_P_IPV6);
@@ -553,7 +553,7 @@
 		iph6 = ipv6_hdr(skb);
 	}
 
-	skb->h.raw = skb->nh.raw;
+	skb->transport_header = skb->network_header;
 	skb_push(skb, sizeof(struct iphdr));
 	skb_reset_network_header(skb);
 	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));