led-backlight bindings

Required properties:
  - compatible: "led-backlight"
  - leds: phandle to a led OF node [0]
  - brightness-levels: Array of distinct LED brightness levels. These
      are in the range from 0 to 255, passed to the LED class driver.
  - default-brightness-level: the default brightness level (index into the
      array defined by the "brightness-levels" property)
  - power-supply: regulator for supply voltage

Optional properties:
  - enable-gpios: contains a single GPIO specifier for the GPIO which enables
                  and disables the backlight (see GPIO binding[1])

[0]: Documentation/devicetree/bindings/leds/common.txt
[1]: Documentation/devicetree/bindings/gpio/gpio.txt

Example:

	backlight {
		compatible = "led-backlight";
		leds = <&backlight_led>;

		brightness-levels = <0 4 8 16 32 64 128 255>;
		default-brightness-level = <6>;

		power-supply = <&vdd_bl_reg>;
		enable-gpios = <&gpio 58 0>;
	};