mlxsw: spectrum: Remove VLANs configuration via SELF flag

When port isn't bridged it is still possible to invoke switchdev ops and
configure the device's VLAN filters.

However, this will require us to use different Router InterFaces (RIFs)
for the same netdev, instead of one per-netdev as with any other
configuration.

Taking the above into account and the fact that this functionality is
questionable with regards to the device's normal use-case, remove it and
instead return an error.

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>