arm64: dts: apm: Update GPIO standby controller DT node for X-Gene v2 platforms

xgene-gpio-sb driver now supports configuring some GPIO pins
as interrupt pins. This patch adds the required fields for GPIO
standby controller DT node of X-Gene v2 platform to work with
this new driver change.
Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: Duc Dang <dhdang@apm.com>

arch/arm64/boot/dts/apm/apm-shadowcat.dtsi

@@ -598,6 +598,12 @@ sbgpio: gpio@17001000{
 				     <0x0 0x2d 0x1>,
 				     <0x0 0x2e 0x1>,
 				     <0x0 0x2f 0x1>;
+			interrupt-parent = <&gic>;
+			#interrupt-cells = <2>;
+			interrupt-controller;
+			apm,nr-gpios = <22>;
+			apm,nr-irqs = <8>;
+			apm,irq-start = <8>;
 		};
 
 		sgenet0: ethernet@1f610000 {