net: dsa: b53: detect BCM5325 variants

We need to be able to differentiate the BCM5325 variants because:
- BCM5325M switches lack the ARLIO_PAGE->VLAN_ID_IDX register.
- BCM5325E have less 512 ARL buckets instead of 1024.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20250614080000.1884236-5-noltari@gmail.com


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