net: dsa: b53: fix flushing old pvid VLAN on pvid change

Presumably the intention here was to flush the VLAN of the old pvid, not
the added VLAN again, which we already flushed before.

Fixes: a2482d2c ("net: dsa: b53: Plug in 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/20250429201710.330937-5-jonas.gorski@gmail.com


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