Hall sensor driver

Hall sensor is a switch. It senses magnetic field change and trigger interrupts to cpu.

Required properties:

 - compatible		: Should be "hall-switch".
 - pinctrl-names	: Pinctrl configuration names of this sensor driver.
				Should be "default".
 - interrupt-parent	: Parent of interrupt.
 - interrupts		: Hall Sensor interrupts to indicate new data ready or events.
 - vddio-supply		: Analog power supply needed to power device.
 - linux,gpio-int	: Irq gpio which is to provide interrupts to host.
 - linux,min-uv		: Device required minimum voltage.
 - linux,max-uv		: Device required max voltage.

Optional properties:

 - linux,wakeup		: Boolean to select interrupt wakeup or not, if this property is defined
				device will wakeup system.

Example:
 &soc {
	hall {
		compatible = "hall-switch";
		pinctrl-names = "default";
		pinctrl-0 = <&hall_sensor_int_default>;
		interrupt-parent = <&msm_gpio>;
		interrupts = <36 0x2003>;
		vddio-supply = <&pm8909_l6>;
		linux,gpio-int = <&msm_gpio 36 0x1>;
		linux,wakeup;
		linux,min-uv = <1650000>;
		linux,max-uv = <3300000>;
	};
 };