riscv: dts: sophgo: add reserved memory node for CV1800B

The original dts of CV1800B has a weird memory length as it
contains reserved memory for coprocessor. Make this area a
separate node so it can get the real memory length.

Link: https://lore.kernel.org/r/IA1PR20MB49531F274753B04A5547DB59BB052@IA1PR20MB4953.namprd20.prod.outlook.comSigned-off-by: Inochi Amaoto <inochiama@outlook.com>
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>

arch/riscv/boot/dts/sophgo/cv1800b-milkv-duo.dts

@@ -23,9 +23,15 @@ chosen {
 		stdout-path = "serial0:115200n8";
 	};
 
-	memory@80000000 {
-		device_type = "memory";
-		reg = <0x80000000 0x3f40000>;
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		coprocessor_rtos: region@83f40000 {
+			reg = <0x83f40000 0xc0000>;
+			no-map;
+		};
 	};
 };
 

arch/riscv/boot/dts/sophgo/cv1800b.dtsi

@@ -7,6 +7,11 @@
 
 / {
 	compatible = "sophgo,cv1800b";
+
+	memory@80000000 {
+		device_type = "memory";
+		reg = <0x80000000 0x4000000>;
+	};
 };
 
 &plic {