TPS65023 family of regulators

Required properties:
- compatible: Must be one of the following.
	"ti,tps65020",
	"ti,tps65021",
	"ti,tps65023",
- reg: I2C slave address
- regulators: list of regulators provided by this controller, must be named
  after their hardware counterparts: VDCDC[1-3] and LDO[1-2]
- regulators: This is the list of child nodes that specify the regulator
  initialization data for defined regulators. The definition for each of
  these nodes is defined using the standard binding for regulators found at
  Documentation/devicetree/bindings/regulator/regulator.txt.

Each regulator is defined using the standard binding for regulators.

Example:

	tps65023@48 {
		compatible = "ti,tps65023";
		reg = <0x48>;

		regulators {
			VDCDC1 {
				regulator-name = "vdd_mpu";
				regulator-always-on;
				regulator-min-microvolt = <1200000>;
				regulator-max-microvolt = <1200000>;
			};

			VDCDC2 {
				regulator-name = "vdd_core";
				regulator-always-on;
				regulator-min-microvolt = <3300000>;
				regulator-max-microvolt = <3300000>;
			};

			VDCDC3 {
				regulator-name = "vdd_io";
				regulator-always-on;
				regulator-min-microvolt = <1800000>;
				regulator-max-microvolt = <1800000>;
			};

			LDO1 {
				regulator-name = "vdd_usb18";
				regulator-always-on;
				regulator-min-microvolt = <1800000>;
				regulator-max-microvolt = <1800000>;
			};

			LDO2 {
				regulator-name = "vdd_usb33";
				regulator-always-on;
				regulator-min-microvolt = <3300000>;
				regulator-max-microvolt = <3300000>;
			};
		};
	};