ina2xx properties

Required properties:
- compatible: Must be one of the following:
	- "ti,ina209" for ina209
	- "ti,ina219" for ina219
	- "ti,ina220" for ina220
	- "ti,ina226" for ina226
	- "ti,ina230" for ina230
	- "ti,ina231" for ina231
	- "ti,ina234" for ina234
	- "ti,ina236" for ina236
- reg: I2C address

Alert types

- shunt overvoltage  : 15
- shunt undervoltage : 14
- bus overvoltage    : 13
- bus undervoltage   : 12
- power overlimit    : 11

Optional properties:

- shunt-resistor
	Shunt resistor value in micro-Ohm
- alert
	IRQ from ina2xx to indicate an alert
- alert-type
	configurable type of alert e.g. bus under voltage,
	see above
- alert-limit
	configurable value at which an alert will trigger

Example:

ina236@44 {
	compatible = "ti,ina236";
	reg = <0x44>;
	shunt-resistor = <1000>;
	interrupts-extended = <&tlmm 32 IRQ_TYPE_EDGE_FALLING>;
	interrupt-names = "alert";
	alert-type = <12>; /* bus undervoltage */
	alert-limit = <10800>; /* 10,8V */
};