ramips: mt7621: add IRQ for GPIO node

This makes interrupt-based gpio-keys working.

Signed-off-by: Chuanhong Guo <[email protected]>

target/linux/ramips/dts/mt7621.dtsi

@@ -76,6 +76,9 @@
 			compatible = "mtk,mt7621-gpio";
 			reg = <0x600 0x100>;
 
+			interrupt-parent = <&gic>;
+			interrupts = <GIC_SHARED 12 IRQ_TYPE_LEVEL_HIGH>;
+
 			gpio0: bank@0 {
 				reg = <0>;
 				compatible = "mtk,mt7621-gpio-bank";