This is slightly different to the other switches - the VLAN table
(VTU) programs in the vlan port mapping /and/ the port config
(tagged, untagged, passthrough, any.)
So:
* Add VTU operations to program the VTU (vlan table)
* abstract out the mirror-disable function so it's .. well, a function.
* setup the port to have a dot1q configuration for dot1q - the
port security is VLAN (not per-port VLAN) and requires an entry
in the VLAN table;
* add set_dot1q / get_dot1q to program the VLAN table;
* since the tagged/untagged ports are now programmed into the VTU,
rather than global - plumb the ports /and/ untagged ports bitmaps
through the arswitch API.
Tested:
* AP135 - QCA9558 SoC + AR8327N switch