bridge: Use BR_INPUT_SKB_CB on xmit path

this patch makes BR_INPUT_SKB_CB available on the xmit path so
that we could avoid passing the br pointer around for the purpose
of collecting device statistics.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 1a99c4e..be35629 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -26,6 +26,8 @@
 	const unsigned char *dest = skb->data;
 	struct net_bridge_fdb_entry *dst;
 
+	BR_INPUT_SKB_CB(skb)->brdev = dev;
+
 	dev->stats.tx_packets++;
 	dev->stats.tx_bytes += skb->len;