Device Tree bindings for Arm Komeda display driver

Required properties:
- compatible: Should be "arm,mali-d71"
- reg: Physical base address and length of the registers in the system
- interrupts: the interrupt line number of the device in the system
- clocks: A list of phandle + clock-specifier pairs, one for each entry
    in 'clock-names'
- clock-names: A list of clock names. It should contain:
      - "aclk": for the main processor clock
- #address-cells: Must be 1
- #size-cells: Must be 0
- iommus: configure the stream id to IOMMU, Must be configured if want to
    enable iommu in display. for how to configure this node please reference
        devicetree/bindings/iommu/arm,smmu-v3.txt,
        devicetree/bindings/iommu/iommu.txt

Required properties for sub-node: pipeline@nq
Each device contains one or two pipeline sub-nodes (at least one), each
pipeline node should provide properties:
- reg: Zero-indexed identifier for the pipeline
- clocks: A list of phandle + clock-specifier pairs, one for each entry
    in 'clock-names'
- clock-names: should contain:
      - "pxclk": pixel clock

- port: each pipeline connect to an encoder input port. The connection is
    modeled using the OF graph bindings specified in
    Documentation/devicetree/bindings/graph.txt

Optional properties:
  - memory-region: phandle to a node describing memory (see
    Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt)
    to be used for the framebuffer; if not present, the framebuffer may
    be located anywhere in memory.

Example:
/ {
	...

	dp0: display@c00000 {
		#address-cells = <1>;
		#size-cells = <0>;
		compatible = "arm,mali-d71";
		reg = <0xc00000 0x20000>;
		interrupts = <0 168 4>;
		clocks = <&dpu_aclk>;
		clock-names = "aclk";
		iommus = <&smmu 0>, <&smmu 1>, <&smmu 2>, <&smmu 3>,
			<&smmu 4>, <&smmu 5>, <&smmu 6>, <&smmu 7>,
			<&smmu 8>, <&smmu 9>;

		dp0_pipe0: pipeline@0 {
			clocks = <&fpgaosc2>;
			clock-names = "pxclk";
			reg = <0>;

			port {
				dp0_pipe0_out: endpoint {
					remote-endpoint = <&db_dvi0_in>;
				};
			};
		};

		dp0_pipe1: pipeline@1 {
			clocks = <&fpgaosc2>;
			clock-names = "pxclk";
			reg = <1>;

			port {
				dp0_pipe1_out: endpoint {
					remote-endpoint = <&db_dvi1_in>;
				};
			};
		};
	};
	...
};