net: bridge: vlan: don't notify to switchdev master VLANs without BRENTRY flag

When a VLAN is added to a bridge port and it doesn't exist on the bridge
device yet, it gets created for the multicast context, but it is
'hidden', since it doesn't have the BRENTRY flag yet:

ip link add br0 type bridge && ip link set swp0 master br0
bridge vlan add dev swp0 vid 100 # the master VLAN 100 gets created
bridge vlan add dev br0 vid 100 self # that VLAN becomes brentry just now

All switchdev drivers ignore switchdev notifiers for VLAN entries which
have the BRENTRY unset, and for good reason: these are merely private
data structures used by the bridge driver. So we might just as well not
notify those at all.

Cleanup in the switchdev drivers that check for the BRENTRY flag is now
possible, and will be handled separately, since those checks just became
dead code.

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