PM / Domains: Add DT bindings for the R-Car System Controller

DT bindings for the Renesas R-Car System Controller

== System Controller Node ==

The R-Car System Controller provides power management for the CPU cores and

various coprocessors.

Required properties:

  - compatible: Must contain exactly one of the following:

      - "renesas,r8a7779-sysc" (R-Car H1)

      - "renesas,r8a7790-sysc" (R-Car H2)

      - "renesas,r8a7791-sysc" (R-Car M2-W)

      - "renesas,r8a7792-sysc" (R-Car V2H)

      - "renesas,r8a7793-sysc" (R-Car M2-N)

      - "renesas,r8a7794-sysc" (R-Car E2)

      - "renesas,r8a7795-sysc" (R-Car H3)

  - reg: Address start and address range for the device.

  - #power-domain-cells: Must be 1.

Example:

	sysc: system-controller@e6180000 {

		compatible = "renesas,r8a7791-sysc";

		reg = <0 0xe6180000 0 0x0200>;

		#power-domain-cells = <1>;

	};

== PM Domain Consumers ==

Devices residing in a power area must refer to that power area, as documented

by the generic PM domain bindings in

Documentation/devicetree/bindings/power/power_domain.txt.

Required properties:

  - power-domains: A phandle and symbolic PM domain specifier, as defined in

		   <dt-bindings/power/r8a77*-sysc.h>.

Example:

	L2_CA15: cache-controller@0 {

		compatible = "cache";

		power-domains = <&sysc R8A7791_PD_CA15_SCU>;

		cache-unified;

		cache-level = <2>;

	};