The ftgmac100 NIC supports VLAN tag insertion and the MAC engine also
has a control to remove VLAN tags from received packets.

The VLAN control bits and VLAN tag information are contained in the
second word of the transmit and receive descriptors. The Insert VLAN
bit and the VLAN Tag available bit are only valid in the first segment
of the packet.
Signed-off-by: NCédric Le Goater <clg@kaod.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180530061711.23673-3-clg@kaod.org
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>