mlxsw: spectrum: Don't report VLAN for 802.1D FDB entries

When dumping the hardware FDB we should report entries pointing to VLAN
devices with VLAN 0, as packets coming into the bridge are untagged.
Likewise, pass FDB_{ADD,DEL} notifications with VLAN 0 for these
devices.

Fixes: 54a73201 ("mlxsw: spectrum: Adjust switchdev ops for VLAN devices")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>