Monolithic Power Systems MP8867/MP8869 voltage regulator

Required properties:
- compatible: Must be one of the following.
	"mps,mp8867"
	"mps,mp8869"
- reg: I2C slave address.
- enable-gpios: enable gpios.
- mps,fb-voltage-divider: An array of two integers containing the resistor
  values R1 and R2 of the feedback voltage divider in kilo ohms.

Optional properties:
- mps,switch-frequency-hz: The valid switch frequency in Hertz. Available values
  are: 500000, 750000, 1000000, 1250000, 1500000

Any property defined as part of the core regulator binding, defined in
./regulator.txt, can also be used.

Example:

	vcpu: regulator@62 {
		compatible = "mps,mp8869";
		regulator-name = "vcpu";
		regulator-min-microvolt = <700000>;
		regulator-max-microvolt = <850000>;
		regulator-always-on;
		regulator-boot-on;
		enable-gpios = <&porta 1 GPIO_ACTIVE_LOW>;
		mps,fb-voltage-divider = <80 240>;
		reg = <0x62>;
	};
