LED connected to GPIO

Required properties:
- compatible : should be "gpio-led".
- label : (optional) the label for this LED. If omitted, the label is
  taken from the node name (excluding the unit address).
- gpios : should specify LED GPIO.

Example:

led@0 {
	compatible = "gpio-led";
	label = "hdd";
	gpios = <&mcu_pio 0 1>;
};
