arm64: dts: rockchip: Use default-state for power LED for Radxa boards

arm64: dts: rockchip: Use default-state for power LED for Radxa boards

Currently, on Radxa boards, the power LED is turned on immediately
after power-up, independent of software control. The heartbeat LED and
other available LEDs are subsequently turned on by the initial
software, such as U-Boot, to indicate software is running.

However, the device tree description for this behavior is inconsistent
and fragmented, with definitions split between the main Linux DTS
files and separate U-Boot files (u-boot/arch/arm/dts/*-u-boot.dtsi).

This patch addresses the inconsistency for the power LED by using
default-state = "on" instead of linux,default-trigger = "default-on".

Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Link: https://patch.msgid.link/20251113124222.4691-2-naoki@radxa.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>