Synaptics TD4310 I2C touchscreen controller

Required properties:
 - compatible: "synaptics,dsx"
 - gpios: 	the reset and interrupt GPIO number
 - reg: 	I2C slave address of the chip

Example nodes:

&i2c3 {
	/* ... */
	synaptics-touch@20 {
		compatible = "synaptics,dsx";
		reg = <0x20>;
		gpios = <&ap_gpio 145 GPIO_ACTIVE_HIGH
			&ap_gpio 144 GPIO_ACTIVE_HIGH>;
	};
	/* ... */
};
