Binding for RGB LEDs connected to AW2013.

AWINIC AW2013 RGB LED driver is used to provide red/green/blue
led blink or glowing to notify user for different system events,
such as missed call, new sms, low battery. AW2013 RGB LED is
connected through I2C.

Required properties:
 - compatible		: should be compatible = "awinic,aw2013"
 - reg			: i2c slave address of the device
 - vdd-supply		: Power supply needed to power up the device
 - vcc-supply		: Power source required to power up i2c bus

LED required sub-node properties:
 - aw2013,name		: name of the LED
 - aw2013,id		: id of the LED
 - aw2013,max-brightness: max brightness set of the LED
 - aw2013,max-current	: max current set of the LED
 - aw2013,rise-time-ms	: the rise time when led in breathe mode
 - aw2013,hold-time-ms	: the hold time when led in breathe mode
 - aw2013,fall-time-ms	: the fall time when led in breathe mode
 - aw2013,off-time-ms	: the off time when led in breathe mode
			The definition of each time described as
			shown in figure:

			         /-----------\
			        /      |      \
			       /|      |      |\
			      / |      |      | \-----------
			        |hold_time_ms |      |
			        |             |      |
			  rise_time_ms  fall_time_ms |
			                        off_time_ms

Example:

	aw2013@45 {
		compatible = "awinic,aw2013";
		reg = <0x45>;
		vdd-supply = <&pm8909_l17>;
		vcc-supply = <&pm8909_l6>;

		aw2013,red {
			aw2013,name = "red";
			aw2013,id = <0>;
			aw2013,max-brightness = <255>;
			aw2013,max-current = <1>;
			aw2013,rise-time-ms = <2>;
			aw2013,hold-time-ms = <1>;
			aw2013,fall-time-ms = <2>;
			aw2013,off-time-ms = <1>;
		};

		aw2013,green {
			aw2013,name = "green";
			aw2013,id = <1>;
			aw2013,max-brightness = <255>;
			aw2013,max-current = <1>;
			aw2013,rise-time-ms = <2>;
			aw2013,hold-time-ms = <1>;
			aw2013,fall-time-ms = <2>;
			aw2013,off-time-ms = <1>;
		};

		aw2013,blue {
			aw2013,name = "blue";
			aw2013,id = <2>;
			aw2013,max-brightness = <255>;
			aw2013,max-current = <1>;
			aw2013,rise-time-ms = <2>;
			aw2013,hold-time-ms = <1>;
			aw2013,fall-time-ms = <2>;
			aw2013,off-time-ms = <1>;
		};
	};