can: Unify droping of invalid tx skbs and netdev stats

To prevent the CAN drivers to operate on invalid socketbuffers the skbs are
now checked and silently dropped at the xmit-function consistently.

Also the netdev stats are consistently using the CAN data length code (dlc)
for [rx|tx]_bytes now.

Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/can/bfin_can.c b/drivers/net/can/bfin_can.c
index 0ec1524..7e1926e 100644
--- a/drivers/net/can/bfin_can.c
+++ b/drivers/net/can/bfin_can.c
@@ -318,6 +318,9 @@
 	u16 val;
 	int i;
 
+	if (can_dropped_invalid_skb(dev, skb))
+		return NETDEV_TX_OK;
+
 	netif_stop_queue(dev);
 
 	/* fill id */