mediatek: filogic: SDG-8733A: describe the LAN LEDs per hardware

mediatek: filogic: SDG-8733A: describe the LAN LEDs per hardware

The board has three LAN LEDs: white on GPIO 59, amber on GPIO 60
and green on GPIO 68. The old description listed two GPIO LEDs
with swapped colors and drove the green LED from the internal
2.5G PHY.

Describe all three as GPIO LEDs and set the netdev triggers to
match: white 2.5G, green 1G, amber 100M. Drop the PHY LED node
and the LED pinctrl state: the PHY LED pad (2p5gbe_led0, pin 68)
now works as the green LED GPIO, so the PHY drives no LED.

Signed-off-by: Chad Monroe <chad@monroe.io>
Link: https://github.com/openwrt/openwrt/pull/24352
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>