The 88e6085 has a few differences from the other devices in the port
control registers, causing unknown multicast/broadcast packets to get
dropped when using the standard port setup.

At the same time update kconfig to clarify that the mv88e6085 is now
supported.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: David S. Miller <davem@davemloft.net>