bridge: handle process all link-local frames

Any frame addressed to link-local addresses should be processed by local
receive path. The earlier code would process them only if STP was enabled.
Since there are other frames like LACP for bonding, we should always
process them.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>