netdrv intel: always enable VLAN filtering except in promiscous mode

Currently VLAN filtering is enabled when the first VLAN is added.
Obviously before that there's no point in receiving any VLAN packets.
Now that we disable VLAN filtering in promiscous mode, we can keep
the VLAN filters enabled the remaining time.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>