[BRIDGE]: receive path optimization

This improves the bridge local receive path by avoiding going
through another softirq.  The bridge receive path is already being called
from a netif_receive_skb() there is no point in going through another
receiveq round trip.

Recursion is limited because bridge can never be a port of a bridge
so handle_bridge() always returns.

Signed-off-by: David S. Miller <davem@davemloft.net>