ARM: dts: BCM53573: Describe BCM53125 switch ports in the main DTS

BCM53125 always has 5 ports with GPHYs (for LAN/WAN ports) and 2 IMP
ports. It seems the best place to describe that in the main .dtsi.
Device specific bits can go to device .dts files. This will help
avoiding some code duplication.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Link: https://lore.kernel.org/r/20230723195416.7831-2-zajec5@gmail.com


Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>