If the DSA master implements strict address filtering, then the unicast
and multicast addresses kept by the DSA CPU ports should be synchronized
with the address lists of the DSA master.

Note that we want the synchronization of the master's address lists even
if the DSA switch doesn't support unicast/multicast database operations,
on the premises that the packets will be flooded to the CPU in that
case, and we should still instruct the master to receive them. This is
why we do the dev_uc_add() etc first, even if dsa_port_notify() returns
-EOPNOTSUPP. In turn, dev_uc_add() and friends return error only if
memory allocation fails, so it is probably ok to check and propagate
that error code and not just ignore it.
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>