arm64: dts: rockchip: Improve LED config for NanoPi R5S

The NanoPi R5S has 4 GPIO LEDs, a RED one for SYStem power and 3 green
LEDs meant to indicate that a cable is connected to either of the
2.5GbE LAN ports or the 1GbE WAN port.

In the NanoPi R5S schematic (2204; page 19) as well as on the PCB and on
the case, SYS is used and not POWER. So replace 'power' with 'sys'.
But keep the 'power_led' label/phandle even though the kernel doesn't
use it, but it may be used outside of it.

The SYStem LED already had "heartbeat" as its default-trigger.
Set the default-trigger to "netdev" for the NICs so they will show when
LAN1/LAN2/WAN is connected and set their default-state to "off".

Also assign labels as close as possible to the labels on the case, while
still being descriptive enough in their own right.

Signed-off-by: Diederik de Haas <didi.debian@cknow.org>
Link: https://lore.kernel.org/r/20250513170056.96259-1-didi.debian@cknow.org


Signed-off-by: Heiko Stuebner <heiko@sntech.de>