net: dsa: vsc73xx: Add vlan filtering

This patch implements VLAN filtering for the vsc73xx driver.

After starting VLAN filtering, the switch is reconfigured from QinQ to
a simple VLAN aware mode. This is required because VSC73XX chips do not
support inner VLAN tag filtering.

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/20240713211620.1125910-3-paweldembicki@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: CHKDSK88