ARM: mediatek: Add sysirq device node to mt6592 dtsi

Add sysirq node to mt6592.dtsi and also correct timer interrupt flag.
The old setting works because boot loader already set it.
With a sysirq device node, the timer interrupt can use a correct value.
Signed-off-by: Howard Chen <howard.chen@linaro.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm/boot/dts/mt6592.dtsi

@@ -18,7 +18,7 @@
 
 / {
 	compatible = "mediatek,mt6592";
-	interrupt-parent = <&gic>;
+	interrupt-parent = <&sysirq>;
 
 	cpus {
 		#address-cells = <1>;
@@ -81,18 +81,25 @@ rtc_clk: dummy32k {
 	timer: timer@10008000 {
 		compatible = "mediatek,mt6577-timer";
 		reg = <0x10008000 0x80>;
-		interrupts = <GIC_SPI 144 IRQ_TYPE_LEVEL_HIGH>;
+		interrupts = <GIC_SPI 144 IRQ_TYPE_LEVEL_LOW>;
 		clocks = <&system_clk>, <&rtc_clk>;
 		clock-names = "system-clk", "rtc-clk";
 	};
 
+	sysirq: interrupt-controller@10200220 {
+		compatible = "mediatek,mt6592-sysirq", "mediatek,mt6577-sysirq";
+		interrupt-controller;
+		#interrupt-cells = <3>;
+		interrupt-parent = <&gic>;
+		reg = <0x10200220 0x1c>;
+	};
+
 	gic: interrupt-controller@10211000 {
 		compatible = "arm,cortex-a7-gic";
 		interrupt-controller;
 		#interrupt-cells = <3>;
+		interrupt-parent = <&gic>;
 		reg = <0x10211000 0x1000>,
 		      <0x10212000 0x1000>;
 	};
-
 };
-