[NET]: Store skb->timestamp as offset to a base timestamp

Reduces skb size by 8 bytes on 64-bit.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 1beb782..72ee00f 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1217,7 +1217,7 @@
 
 	while (skb != (struct sk_buff *)&tbl->proxy_queue) {
 		struct sk_buff *back = skb;
-		long tdif = back->stamp.tv_usec - now;
+		long tdif = NEIGH_CB(back)->sched_next - now;
 
 		skb = skb->next;
 		if (tdif <= 0) {
@@ -1248,8 +1248,9 @@
 		kfree_skb(skb);
 		return;
 	}
-	skb->stamp.tv_sec  = LOCALLY_ENQUEUED;
-	skb->stamp.tv_usec = sched_next;
+
+	NEIGH_CB(skb)->sched_next = sched_next;
+	NEIGH_CB(skb)->flags |= LOCALLY_ENQUEUED;
 
 	spin_lock(&tbl->proxy_queue.lock);
 	if (del_timer(&tbl->proxy_timer)) {