Atmel touch controller

Required properties:

 - compatible	: should be "atmel,maxtouch-ts"
 - 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.
 - atmel,panel-coords	: touch panel minimum x, minimum y, maximum x and
				maximum y resolution
 - atmel,display-coords : LCD display minimum x, minimum y, maximum x and
				maximum y resolution
 - vdd-supply	: Analog power supply needed to power device
 - avcc-supply		: Power source required to pull up i2c bus
 - atmel,irq-gpio	: irq gpio
 - atmel,reset-gpio	: reset gpio

Optional property:
 - atmel,bl-addr		: bootloader address, by default is looked up
					in mxt_slave_addresses structure
 - atmel,key-codes		: key codes corresponding to keyarray object

Example:
	i2c@f9966000 {
		atmel_maxtouch_ts@4a {
			compatible = "atmel,maxtouch-ts";
			reg = <0x4a>
			interrupt-parent = <&msmgpio>
			interrupts = <48 0x0>;
			vdd-supply = <&pm8941_l18>;
			avdd-supply = <&pm8941_lvs1>;
			atmel,panel-coords = <0 0 479 799>;
			atmel,display-coords = <0 0 479 799>;
			atmel,irq-gpio = <&msmgpio 48 0>;
			atmel,reset-gpio = <&msmgpio 26 0>;
		};
	};
