[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/ipv4/igmp.c b/net/ipv4/igmp.c
index 4695ada..1fc637f 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -333,7 +333,7 @@
 	((u8*)&pip[1])[2] = 0;
 	((u8*)&pip[1])[3] = 0;
 
-	skb->h.raw = skb->nh.raw + sizeof(struct iphdr) + 4;
+	skb->transport_header = skb->network_header + sizeof(struct iphdr) + 4;
 	skb_put(skb, sizeof(*pig));
 	pig = igmpv3_report_hdr(skb);
 	pig->type = IGMPV3_HOST_MEMBERSHIP_REPORT;