batman-adv: Treat NET_XMIT_CN as transmit successfully

The tc could return NET_XMIT_CN as one congestion notification, but
it does not mean the packet is lost. Other modules like ipvlan,
macvlan, and others treat NET_XMIT_CN as success too.

So batman-adv should handle NET_XMIT_CN also as NET_XMIT_SUCCESS.
Signed-off-by: Gao Feng <gfree.wind@gmail.com>
[sven@narfation.org: Moved NET_XMIT_CN handling to batadv_send_skb_packet]
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/send.c

@@ -115,7 +115,7 @@ int batadv_send_skb_packet(struct sk_buff *skb,
 	 * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
 	 * (which is > 0). This will not be treated as an error.
 	 */
-	return dev_queue_xmit(skb);
+	return net_xmit_eval(dev_queue_xmit(skb));
 send_skb_err:
 	kfree_skb(skb);
 	return NET_XMIT_DROP;