packet: report tx_dropped in packet_direct_xmit

Since commit 015f0688f57c ("net: net: add a core netdev->tx_dropped
counter"), we can now account for TX drops from within the core
stack instead of drivers.

Therefore, fix packet_direct_xmit() and increase drop count when we
encounter a problem before driver's xmit function was called (we do
not want to doubly account for it).

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 01039d2..c81a9719 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -275,6 +275,7 @@
 
 	return ret;
 drop:
+	atomic_long_inc(&dev->tx_dropped);
 	kfree_skb(skb);
 	return NET_XMIT_DROP;
 }