net: dsa: b53: fix b53_imp_vlan_setup for BCM5325

CPU port should be B53_CPU_PORT instead of B53_CPU_PORT_25 for
B53_PVLAN_PORT_MASK register.

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Link: https://patch.msgid.link/20250614080000.1884236-14-noltari@gmail.com


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