Hisilicon Hi655x Voltage regulators

Note:
The hi655x regulator control is managed by hi655x Power IC.
So the node of this regulator must be child node of hi655x
PMIC node.

The driver uses the regulator core framework, so please also
take the bindings of regulator.txt for reference.

The valid names for regulators are:

LDO2 LDO7 LDO10 LDO13 LDO14 LDO15 LDO17 LDO19 LDO21 LDO22

Example:
        pmic: pmic@f8000000 {
                compatible = "hisilicon,hi655x-pmic";
		...
		regulators {
			ldo2: LDO2@a21 {
				regulator-compatible = "LDO2_2V8";
				regulator-min-microvolt = <2500000>;
				regulator-max-microvolt = <3200000>;
				regulator-enable-ramp-delay = <120>;
			};
			...
		}
	}
