controller, I'm not sure whether this is also applicable to SiS190
so this feature is only activated on SiS191 controller.
In theory, controller reinitialization is not needed when VLAN tag
configuration is changed, but xclin said controller was not stable
whenever toggling VLAN tag bit. To address that, sge(4)
reinitialize controller for VLAN configuration which seems to work
as expected. VLAN tag information for TX/RX descriptor and
configure bit of RxMacControl register was found by xclin.
Submitted by: xclin <xclin <> cs dot nctu dot edu dot tw > (initial version)
Tested by: xclin <xclin <> cs dot nctu dot edu dot tw >
c186cf13eb