net: dsa: b53: always rejoin default untagged VLAN on bridge leave

While JOIN_ALL_VLAN allows to join all VLANs, we still need to keep the
default VLAN enabled so that untagged traffic stays untagged.

So rejoin the default VLAN even for switches with JOIN_ALL_VLAN support.

Fixes: 48aea33a ("net: dsa: b53: Add JOIN_ALL_VLAN support")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20250429201710.330937-7-jonas.gorski@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>