net: dsa: tag_8021q: stop restoring VLANs from bridge

Right now, our only tag_8021q user, sja1105, has the ability to restore
bridge VLANs on its own, so this logic is unnecessary.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>