net: dsa: b53: implement setting ageing time

b53 supported switches support configuring ageing time between 1 and
1,048,575 seconds, so add an appropriate setter.

This allows b53 to pass the FDB learning test for both vlan aware and
vlan unaware bridges.

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20250510092211.276541-1-jonas.gorski@gmail.com


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