DT binding document for INA219 iio/meter driver.

Required properties:
- compatible: Must be one of
	"ti,ina219"
- reg: I2C slave address of device.

- ti,rail-name: Name of the rail for whose monitoring is required.
- ti,trigger-config: Trigger configuration for the device in trigger mode.
- ti,continuous-config:  Device configuration in continuous mode. In this mode
	device will keep scanning the inputs.
- address-cells: Number of address in child node. Must be 1.
- size-cells: Size of address cell. Must be 0.

Optional properties:
- ti,calibration-data: Calibration data.
- ti,power-lsb: LSB power.
- ti,divisor: Divisor.
- ti,shunt-resistor-mohm: Shunt resistance in milliohm.
- ti,precision-multiplier: Precision multplier.

Example:
	ina219@41{
		compatible = "ti,ina219x";
		reg = <0x41>;
		ti,rail-name = "VDD_BAT_CHG";
		ti,continuous-config = <0x0407>;
		ti,trigger-config = <0x0403>;
		ti,calibration-data = <0x0E90>;
		ti,power-lsb = <6866>;
		ti,divisor = <25>;
		ti,precision-multiplier = <1000>;
	}; 

