net: dsa: ksz: Add STP multicast handling

net: dsa: ksz: Add STP multicast handling

In case the destination address is link local, add override bit into the
switch tag to let such a packet through the switch even if the port is
blocked.

Signed-off-by: Marek Vasut <[email protected]>
Cc: Tristram Ha <[email protected]>
Cc: Vivien Didelot <[email protected]>
Cc: Woojung Huh <[email protected]>
Cc: David S. Miller <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Signed-off-by: David S. Miller <[email protected]>