Synaptics DSX touch controller

Required properties:

 - compatible		: should be "synaptics,dsx"
 - reg			: i2c slave address of the device
 - interrupt-parent	: parent of interrupt
 - interrupts		: touch sample interrupt to indicate presense or release
				of fingers on the panel.
 - synaptics,irq-gpio	: irq gpio
 - synaptics,reset-gpio	: reset gpio

Optional property:
 - vdd-supply			: digital voltage power supply needed to power device
 - avdd-supply			: analog voltage power supply needed to power device
 - synaptics,button-map		: virtual key code mappings to be used
 - synaptics,x-flip		: modify orientation of the x axis
 - synaptics,y-flip		: modify orientation of the y axis
 - synaptics,reset-delay-ms	: reset delay for controller (ms), default 100

Example:
	i2c@f9927000 {
		synaptics@20 {
			compatible = "synaptics,dsx"
			reg = <0x20>;
			interrupt-parent = <&msmgpio>;
			interrupts = <17 0x2>;
			vdd-supply = <&pm8226_l19>;
			avdd-supply = <&pm8226_lvs1>;
			synaptics,reset-gpio = <&msmgpio 16 0x00>;
			synaptics,irq-gpio = <&msmgpio 17 0x00>;
			synaptics,button-map = [8B 66 9E];
			synaptics,reset-delay-ms = <100>;
			synaptics,x-flip;
			synaptics,y-flip;
		};
	};
