LoongArch: Update dts for Loongson-2K1000 to support ISA/LPC

Some Loongson-2K1000 platforms have ISA/LPC devices such as Super-IO,
define an ISA node in the dts file to avoid access error.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: chenhuacai

arch/loongarch/boot/dts/loongson-2k1000.dtsi

@@ -100,6 +100,13 @@
 		#size-cells = <2>;
 		dma-coherent;
 
+		isa@18000000 {
+			compatible = "isa";
+			#size-cells = <1>;
+			#address-cells = <2>;
+			ranges = <1 0x0 0x0 0x18000000 0x4000>;
+		};
+
 		liointc0: interrupt-controller@1fe01400 {
 			compatible = "loongson,liointc-2.0";
 			reg = <0x0 0x1fe01400 0x0 0x40>,