lantiq: remove model name from LED labels

lantiq: remove model name from LED labels

Like in the previous patches for other targets, this will remove
the "devicename" from LED labels in lantiq.

The devicename is removed in DTS files and 01_leds, consolidation
of definitions into DTSI files is done where (easily) possible,
and migration scripts are updated. The DTS/DTSI consolidation is
only performed for files-5.4.

For lantiq,easy98020 some LED definitions have the form
"devicename:function" without the color, so we need to implement
explicit migration for that one.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>