TPS6586x family of regulators

Required properties:
- compatible: "ti,tps6586x"
- reg: I2C slave address
- interrupts: the interrupt outputs of the controller
- #gpio-cells: number of cells to describe a GPIO
- gpio-controller: mark the device as a GPIO controller
- regulators: list of regulators provided by this controller, must be named
  after their hardware counterparts: sm[0-2], ldo[0-9] and ldo_rtc

Each regulator is defined using the standard binding for regulators.

Example:

	pmu: tps6586x@34 {
		compatible = "ti,tps6586x";
		reg = <0x34>;
		interrupts = <0 88 0x4>;

		#gpio-cells = <2>;
		gpio-controller;

		regulators {
			sm0_reg: sm0 {
				regulator-min-microvolt = < 725000>;
				regulator-max-microvolt = <1500000>;
				regulator-boot-on;
				regulator-always-on;
			};

			sm1_reg: sm1 {
				regulator-min-microvolt = < 725000>;
				regulator-max-microvolt = <1500000>;
				regulator-boot-on;
				regulator-always-on;
			};

			sm2_reg: sm2 {
				regulator-min-microvolt = <3000000>;
				regulator-max-microvolt = <4550000>;
				regulator-boot-on;
				regulator-always-on;
			};

			ldo0_reg: ldo0 {
				regulator-name = "PCIE CLK";
				regulator-min-microvolt = <3300000>;
				regulator-max-microvolt = <3300000>;
			};

			ldo1_reg: ldo1 {
				regulator-min-microvolt = < 725000>;
				regulator-max-microvolt = <1500000>;
			};

			ldo2_reg: ldo2 {
				regulator-min-microvolt = < 725000>;
				regulator-max-microvolt = <1500000>;
			};

			ldo3_reg: ldo3 {
				regulator-min-microvolt = <1250000>;
				regulator-max-microvolt = <3300000>;
			};

			ldo4_reg: ldo4 {
				regulator-min-microvolt = <1700000>;
				regulator-max-microvolt = <2475000>;
			};

			ldo5_reg: ldo5 {
				regulator-min-microvolt = <1250000>;
				regulator-max-microvolt = <3300000>;
			};

			ldo6_reg: ldo6 {
				regulator-min-microvolt = <1250000>;
				regulator-max-microvolt = <3300000>;
			};

			ldo7_reg: ldo7 {
				regulator-min-microvolt = <1250000>;
				regulator-max-microvolt = <3300000>;
			};

			ldo8_reg: ldo8 {
				regulator-min-microvolt = <1250000>;
				regulator-max-microvolt = <3300000>;
			};

			ldo9_reg: ldo9 {
				regulator-min-microvolt = <1250000>;
				regulator-max-microvolt = <3300000>;
			};
		};
	};