net: dsa: b53: add support for FDB operations on 5325/5365

BCM5325 and BCM5365 are part of a much older generation of switches which,
due to their limited number of ports and VLAN entries (up to 256) allowed
a single 64-bit register to hold a full ARL entry.
This requires a little bit of massaging when reading, writing and
converting ARL entries in both directions.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Link: https://patch.msgid.link/20250614080000.1884236-6-noltari@gmail.com


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