dst: gigadevice: change usart3 address to lower case

DTS node address should use lower case. This fix an incorrect
gd32f403 usart3 node address.

Signed-off-by: HaiLong Yang <hailong.yang@brainco.cn>

Author: HaiLong Yang

dts/arm/gigadevice/gd32f403/gd32f403.dtsi

@@ -77,9 +77,9 @@
 			label = "USART_2";
 		};
 
-		uart3: usart@40004C00 {
+		uart3: usart@40004c00 {
 			compatible = "gd,gd32-usart";
-			reg = <0x40004C00 0x400>;
+			reg = <0x40004c00 0x400>;
 			interrupts = <52 0>;
 			rcu-periph-clock = <0x714>;
 			status = "disabled";