net: use consume_skb() in place of kfree_skb()

Remove some dropwatch/drop_monitor false positives.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/atm/pppoatm.c

@@ -283,7 +283,7 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
 				kfree_skb(n);
 				goto nospace;
 			}
-			kfree_skb(skb);
+			consume_skb(skb);
 			skb = n;
 			if (skb == NULL)
 				return DROP_PACKET;