net: dsa: lantiq_gswip: drop untagged on VLAN-aware bridge ports with no PVID

net: dsa: lantiq_gswip: drop untagged on VLAN-aware bridge ports with no PVID

Implement the required functionality, as written in
Documentation/networking/switchdev.rst section "Bridge VLAN filtering",
by using the "VLAN Ingress Tag Rule" feature of the switch.

The bit field definitions for this were found while browsing the Intel
dual BSD/GPLv2 licensed drivers for this switch IP.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://patch.msgid.link/787aa807d00b726d75db2a40add215c8b8ba7466.1760566491.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>