MAXIM, MAX77686 regulators

This device uses two drivers:
- drivers/power/pmic/max77686.c (as parent I/O device)
- drivers/power/regulator/max77686.c (for child regulators)

This file describes the binding info for the REGULATOR driver.

First, please read the binding info for the pmic:
- doc/device-tree-bindings/pmic/max77686.txt

Required subnode:
- voltage-regulators: required for the PMIC driver

Required properties:
- regulator-name: used for regulator uclass platform data '.name'

Optional:
- regulator-min-microvolt: minimum allowed Voltage to set
- regulator-max-microvolt: minimum allowed Voltage to set
- regulator-always-on: regulator should be never disabled
- regulator-boot-on: regulator should be enabled by the bootloader

Example:
(subnode of max77686 pmic node)
voltage-regulators {
	ldo1 {
		regulator-name = "VDD_ALIVE_1.0V";
		regulator-min-microvolt = <1000000>;
		regulator-max-microvolt = <1000000>;
		regulator-always-on;
		regulator-boot-on;
	};

	ldo2 {
		regulator-name = "VDDQ_VM1M2_1.2V";
		regulator-min-microvolt = <1200000>;
		regulator-max-microvolt = <1200000>;
		regulator-always-on;
		regulator-boot-on;
	};
	.
	.
	.
	ldo26 {
		regulator-name = "nc";
		regulator-min-microvolt = <3000000>;
		regulator-max-microvolt = <3000000>;
		regulator-always-on;
		regulator-boot-on;
	};

	buck1 {
		regulator-compatible = "BUCK1";
		regulator-name = "VDD_MIF_1.0V";
		regulator-min-microvolt = <8500000>;
		regulator-max-microvolt = <1100000>;
		regulator-always-on;
		regulator-boot-on;
	};
	.
	.
	.
	buck9 {
		regulator-compatible = "BUCK9";
		regulator-name = "nc";
		regulator-min-microvolt = <1200000>;
		regulator-max-microvolt = <1200000>;
	};
};