dt/bindings: drm/komeda: Add DT bindings for ARM display processor D71

Add DT bindings documentation for the ARM display processor D71 and later
IPs.

Changes in v4:
- Deleted unnecessary address-cells, size-cells [Liviu Dudau]

Changes in v3:
- Deleted unnecessary property: interrupt-names.
- Dropped 'ports' and moving 'port' up a level.
Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
[moved in the same directory as the other Arm display bindings]
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

Documentation/devicetree/bindings/display/arm,komeda.txt

+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:
+      - "mclk": for the main processor clock
+      - "pclk": for the APB interface clock
+- #address-cells: Must be 1
+- #size-cells: Must be 0
+
+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
+      - "aclk": AXI interface 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_mclk>, <&dpu_aclk>;
+		clock-names = "mclk", "pclk";
+
+		dp0_pipe0: pipeline@0 {
+			clocks = <&fpgaosc2>, <&dpu_aclk>;
+			clock-names = "pxclk", "aclk";
+			reg = <0>;
+
+			port {
+				dp0_pipe0_out: endpoint {
+					remote-endpoint = <&db_dvi0_in>;
+				};
+			};
+		};
+
+		dp0_pipe1: pipeline@1 {
+			clocks = <&fpgaosc2>, <&dpu_aclk>;
+			clock-names = "pxclk", "aclk";
+			reg = <1>;
+
+			port {
+				dp0_pipe1_out: endpoint {
+					remote-endpoint = <&db_dvi1_in>;
+				};
+			};
+		};
+	};
+	...
+};