base-files: add more name source to get_dt_led helper function

Not all LED driver are using the label devicetree property for the led
name. Add support for the TI/National Semiconductor LP55xx Led Drivers,
which are using the chan-name property for the led name, as fallback.

Signed-off-by: Mathias Kresin <dev@kresin.me>

package/base-files/files/lib/functions/leds.sh

@@ -8,7 +8,10 @@ get_dt_led() {
 	local nodepath="$basepath/aliases/led-$1"
 
 	[ -f "$nodepath" ] && ledpath=$(cat "$nodepath")
-	[ -n "$ledpath" ] && label=$(cat "$basepath$ledpath/label")
+	[ -n "$ledpath" ] && \
+		label=$(cat "$basepath$ledpath/label" 2>/dev/null) || \
+		label=$(cat "$basepath$ledpath/chan-name" 2>/dev/null) || \
+		echo "led label not found" 1>&2
 
 	echo "$label"
 }