dt-bindings: ARM: Mediatek: Document devicetree bindings for clock controllers

This adds the binding documentation for the mmsys, imgsys, vdecsys,
vencsys and vencltsys controllers found on Mediatek SoCs.

Signed-off-by: James Liao <[e-mail]>
Reviewed-by: Daniel Kurtz <[e-mail]>

Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt

···
+Mediatek imgsys controller
+============================
+
+The Mediatek imgsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-imgsys", "syscon"
+- #clock-cells: Must be 1
+
+The imgsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+imgsys: clock-controller@15000000 {
+	compatible = "mediatek,mt8173-imgsys", "syscon";
+	reg = <0 0x15000000 0 0x1000>;
+	#clock-cells = <1>;
+};

Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt

···
+Mediatek mmsys controller
+============================
+
+The Mediatek mmsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-mmsys", "syscon"
+- #clock-cells: Must be 1
+
+The mmsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+mmsys: clock-controller@14000000 {
+	compatible = "mediatek,mt8173-mmsys", "syscon";
+	reg = <0 0x14000000 0 0x1000>;
+	#clock-cells = <1>;
+};

Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt

···
+Mediatek vdecsys controller
+============================
+
+The Mediatek vdecsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-vdecsys", "syscon"
+- #clock-cells: Must be 1
+
+The vdecsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+vdecsys: clock-controller@16000000 {
+	compatible = "mediatek,mt8173-vdecsys", "syscon";
+	reg = <0 0x16000000 0 0x1000>;
+	#clock-cells = <1>;
+};

Documentation/devicetree/bindings/arm/mediatek/mediatek,vencltsys.txt

···
+Mediatek vencltsys controller
+============================
+
+The Mediatek vencltsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-vencltsys", "syscon"
+- #clock-cells: Must be 1
+
+The vencltsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+vencltsys: clock-controller@19000000 {
+	compatible = "mediatek,mt8173-vencltsys", "syscon";
+	reg = <0 0x19000000 0 0x1000>;
+	#clock-cells = <1>;
+};

Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt

···
+Mediatek vencsys controller
+============================
+
+The Mediatek vencsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-vencsys", "syscon"
+- #clock-cells: Must be 1
+
+The vencsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+vencsys: clock-controller@18000000 {
+	compatible = "mediatek,mt8173-vencsys", "syscon";
+	reg = <0 0x18000000 0 0x1000>;
+	#clock-cells = <1>;
+};