net: sk_drops consolidation part 2

- skb_kill_datagram() can increment sk->sk_drops itself, not callers.

- UDP on IPV4 & IPV6 dropped frames (because of bad checksum or policy checks) increment sk_drops

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 1c6cf3a..4d57f5e 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -262,6 +262,7 @@
 	}
 
 	kfree_skb(skb);
+	atomic_inc(&sk->sk_drops);
 	sk_mem_reclaim_partial(sk);
 
 	return err;