LEDs connected to is31fl319x LED controller chip

Required properties:
- compatible : Should be any of
	"issi,is31fl3190"
	"issi,is31fl3191"
	"issi,is31fl3193"
	"issi,is31fl3196"
	"issi,is31fl3199"
	"si-en,sn3199".
- #address-cells: Must be 1.
- #size-cells: Must be 0.
- reg: 0x64, 0x65, 0x66, or 0x67.

Optional properties:
- audio-gain-db : audio gain selection for external analog modulation input.
	Valid values: 0 - 21, step by 3 (rounded down)
	Default: 0

Each led is represented as a sub-node of the issi,is31fl319x device.
There can be less leds subnodes than the chip can support but not more.

Required led sub-node properties:
- reg : number of LED line
	Valid values: 1 - number of leds supported by the chip variant.

Optional led sub-node properties:
- label : see Documentation/devicetree/bindings/leds/common.txt.
- linux,default-trigger :
	see Documentation/devicetree/bindings/leds/common.txt.
- led-max-microamp : (optional)
	Valid values: 5000 - 40000, step by 5000 (rounded down)
	Default: 20000 (20 mA)
	Note: a driver will take the lowest of all led limits since the
	chip has a single global setting. The lowest value will be chosen
	due to the PWM specificity, where lower brightness is achieved
	by reducing the dury-cycle of pulses and not the current, which
	will always have its peak value equal to led-max-microamp.

Examples:

fancy_leds: leds@65 {
	compatible = "issi,is31fl3196";
	#address-cells = <1>;
	#size-cells = <0>;
	reg = <0x65>;

	red_aux: led@1 {
		label = "red:aux";
		reg = <1>;
		led-max-microamp = <10000>;
	};

	green_power: led@5 {
		label = "green:power";
		reg = <5>;
		linux,default-trigger = "default-on";
	};
};