arm64: dts: mt8173: Add subsystem clock controller device nodes

This patch adds device nodes providing subsystem clocks on MT8173,
includes mmsys, imgsys, vdecsys, vencsys and vencltsys.
Signed-off-by: James Liao <jamesjj.liao@mediatek.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt8173.dtsi

@@ -116,6 +116,13 @@ clk32k: oscillator@1 {
 		clock-output-names = "clk32k";
 	};
 
+	cpum_ck: oscillator@2 {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <0>;
+		clock-output-names = "cpum_ck";
+	};
+
 	timer {
 		compatible = "arm,armv8-timer";
 		interrupt-parent = <&gic>;
@@ -500,6 +507,36 @@ mmc3: mmc@11260000 {
 			clock-names = "source", "hclk";
 			status = "disabled";
 		};
+
+		mmsys: clock-controller@14000000 {
+			compatible = "mediatek,mt8173-mmsys", "syscon";
+			reg = <0 0x14000000 0 0x1000>;
+			#clock-cells = <1>;
+		};
+
+		imgsys: clock-controller@15000000 {
+			compatible = "mediatek,mt8173-imgsys", "syscon";
+			reg = <0 0x15000000 0 0x1000>;
+			#clock-cells = <1>;
+		};
+
+		vdecsys: clock-controller@16000000 {
+			compatible = "mediatek,mt8173-vdecsys", "syscon";
+			reg = <0 0x16000000 0 0x1000>;
+			#clock-cells = <1>;
+		};
+
+		vencsys: clock-controller@18000000 {
+			compatible = "mediatek,mt8173-vencsys", "syscon";
+			reg = <0 0x18000000 0 0x1000>;
+			#clock-cells = <1>;
+		};
+
+		vencltsys: clock-controller@19000000 {
+			compatible = "mediatek,mt8173-vencltsys", "syscon";
+			reg = <0 0x19000000 0 0x1000>;
+			#clock-cells = <1>;
+		};
 	};
 };