arm64: dts: mediatek: mt6795: Add CPUX system timer node

Add a node for mt6795-systimer: this is necessary to start the
System Timer(s) for all cores, finally making CNTVCT_EL0 usable.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220729093536.27623-1-angelogioacchino.delregno@collabora.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt6795.dtsi

@@ -230,6 +230,14 @@ sysirq: intpol-controller@10200620 {
 			reg = <0 0x10200620 0 0x20>;
 		};
 
+		systimer: timer@10200670 {
+			compatible = "mediatek,mt6795-systimer";
+			reg = <0 0x10200670 0 0x10>;
+			interrupts = <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&system_clk>;
+			clock-names = "clk13m";
+		};
+
 		gic: interrupt-controller@10221000 {
 			compatible = "arm,gic-400";
 			#interrupt-cells = <3>;