ARM: mediatek: add UART dts for mt8127 and mt8135

This add dts support for mt8127 and mt8135 SOC UART

Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm/boot/dts/mt8127.dtsi

@@ -64,6 +64,12 @@
 			clock-frequency = <32000>;
 			#clock-cells = <0>;
 		};
+
+		uart_clk: dummy26m {
+			compatible = "fixed-clock";
+			clock-frequency = <26000000>;
+			#clock-cells = <0>;
+                };
 	};
 
 	soc {
@@ -100,5 +106,37 @@
 			      <0 0x10214000 0 0x2000>,
 			      <0 0x10216000 0 0x2000>;
 		};
+
+		uart0: serial@11006000 {
+			compatible = "mediatek,mt8127-uart","mediatek,mt6577-uart";
+			reg = <0 0x11002000 0 0x400>;
+			interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&uart_clk>;
+			status = "disabled";
+		};
+
+		uart1: serial@11007000 {
+			compatible = "mediatek,mt8127-uart","mediatek,mt6577-uart";
+			reg = <0 0x11003000 0 0x400>;
+			interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&uart_clk>;
+			status = "disabled";
+		};
+
+		uart2: serial@11008000 {
+			compatible = "mediatek,mt8127-uart","mediatek,mt6577-uart";
+			reg = <0 0x11004000 0 0x400>;
+			interrupts = <GIC_SPI 53 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&uart_clk>;
+			status = "disabled";
+		};
+
+		uart3: serial@11009000 {
+			compatible = "mediatek,mt8127-uart","mediatek,mt6577-uart";
+			reg = <0 0x11005000 0 0x400>;
+			interrupts = <GIC_SPI 54 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&uart_clk>;
+			status = "disabled";
+		};
 	};
 };