ARM: mediatek: dts: Add uart to mt6589

This patch adds the uart ports to the device tree of Mediatek mt6589 SoC.
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm/boot/dts/mt6589.dtsi

@@ -65,6 +65,12 @@ rtc_clk: dummy32k {
 			clock-frequency = <32000>;
 			#clock-cells = <0>;
 		};
+
+		uart_clk: dummy26m {
+			compatible = "fixed-clock";
+			clock-frequency = <26000000>;
+			#clock-cells = <0>;
+		};
 	};
 
 	soc {
@@ -100,5 +106,37 @@ gic: interrupt-controller@10211000 {
 			      <0x10214000 0x2000>,
 			      <0x10216000 0x2000>;
 		};
+
+		uart0: serial@11006000 {
+			compatible = "mediatek,mt6577-uart";
+			reg = <0x11006000 0x400>;
+			interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&uart_clk>;
+			status = "disabled";
+		};
+
+		uart1: serial@11007000 {
+			compatible = "mediatek,mt6577-uart";
+			reg = <0x11007000 0x400>;
+			interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&uart_clk>;
+			status = "disabled";
+		};
+
+		uart2: serial@11008000 {
+			compatible = "mediatek,mt6577-uart";
+			reg = <0x11008000 0x400>;
+			interrupts = <GIC_SPI 53 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&uart_clk>;
+			status = "disabled";
+		};
+
+		uart3: serial@11009000 {
+			compatible = "mediatek,mt6577-uart";
+			reg = <0x11009000 0x400>;
+			interrupts = <GIC_SPI 54 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&uart_clk>;
+			status = "disabled";
+		};
 	};
 };