apm821xx: implement new LED label naming scheme

apm821xx: implement new LED label naming scheme

This patch updates all current APM82181 devices over to that
"new LED naming scheme". This includes many updates to the
device-tree:
	- dropped the deprecated, but beloved "label" property.
	- rename all DT leds node names to led-#.
	- add function and color properties.
	- utilized panic-indicator property.
	- dropped led- aliases (see below).

migration scripts for all devices are included.

For more information. See:
<https://www.kernel.org/doc/html/latest/leds/leds-class.html>

For the future: It looks like the color+function properties
won over the dt-alias / label. This will need to be wired up
into openwrt eventually. For APM821xx the situation is that
all devices have a dedicated power and fault indicator.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>