arm64: dts: k3-am6: Add "socionext,synquacer-pre-its" property to gic_its

GIC_ITS used in AM654 platform has the same configuration as that of
GIC_ITS used in Socionext SoCs. Add "socionext,synquacer-pre-its"
property to get PCI MSI working.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>

arch/arm64/boot/dts/ti/k3-am65-main.dtsi

@@ -44,6 +44,7 @@ gic500: interrupt-controller@1800000 {
 		gic_its: gic-its@18200000 {
 			compatible = "arm,gic-v3-its";
 			reg = <0x00 0x01820000 0x00 0x10000>;
+			socionext,synquacer-pre-its = <0x1000000 0x400000>;
 			msi-controller;
 			#msi-cells = <1>;
 		};