LEDs connected to tca6507

Required properties:
- compatible : should be : "ti,tca6507".
- #address-cells: must be 1
- #size-cells: must be 0
- reg: typically 0x45.

Optional properties:
- gpio-controller: allows lines to be used as output-only GPIOs.
- #gpio-cells: if present, must be 0.

Each led is represented as a sub-node of the ti,tca6507 device.

LED sub-node properties:
- label : (optional) see Documentation/devicetree/bindings/leds/common.txt
- reg : number of LED line (could be from 0 to 6)
- linux,default-trigger : (optional)
   see Documentation/devicetree/bindings/leds/common.txt
- compatible: either "led" (the default) or "gpio".

Examples:

tca6507@45 {
	compatible = "ti,tca6507";
	#address-cells = <1>;
	#size-cells = <0>;
	reg = <0x45>;

	gpio-controller;
	#gpio-cells = <2>;

	led0: red-aux@0 {
		label = "red:aux";
		reg = <0x0>;
	};

	led1: green-aux@1 {
		label = "green:aux";
		reg = <0x5>;
		linux,default-trigger = "default-on";
	};

	wifi-reset@6 {
		reg = <0x6>;
		compatible = "gpio";
	};
};