UniPhier SoCs pin controller

Required properties:
- compatible: should be one of the following:
    "socionext,uniphier-ld4-pinctrl"  - for LD4 SoC
    "socionext,uniphier-pro4-pinctrl" - for Pro4 SoC
    "socionext,uniphier-sld8-pinctrl" - for sLD8 SoC
    "socionext,uniphier-pro5-pinctrl" - for Pro5 SoC
    "socionext,uniphier-pxs2-pinctrl" - for PXs2 SoC
    "socionext,uniphier-ld6b-pinctrl" - for LD6b SoC
    "socionext,uniphier-ld11-pinctrl" - for LD11 SoC
    "socionext,uniphier-ld20-pinctrl" - for LD20 SoC
    "socionext,uniphier-pxs3-pinctrl" - for PXs3 SoC

Note:
The UniPhier pinctrl should be a subnode of a "syscon" compatible node.

Example:
	soc-glue@5f800000 {
		compatible = "socionext,uniphier-pro4-soc-glue",
			     "simple-mfd", "syscon";
		reg = <0x5f800000 0x2000>;

		pinctrl: pinctrl {
			compatible = "socionext,uniphier-pro4-pinctrl";
		};
	};