net: dsa: mt7530: fix tagged frames pass-through in VLAN-unaware mode

net: dsa: mt7530: fix tagged frames pass-through in VLAN-unaware mode

In VLAN-unaware mode, the Egress Tag (EG_TAG) field in Port VLAN
Control register must be set to Consistent to let tagged frames pass
through as is, otherwise their tags will be stripped.

Fixes: 83163f7dca56 ("net: dsa: mediatek: add VLAN support for MT7530")
Signed-off-by: DENG Qingfang <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Tested-by: René van Dorst <[email protected]>
Signed-off-by: David S. Miller <[email protected]>