boards: rts5912_evb: set shell-uart

Set a zephyr,shell-uart chosen node so this board can be used with the
shell module.

Signed-off-by: Fabio Baltieri <[email protected]>

Author: fabiobaltieri

boards/realtek/rts5912_evb/rts5912_evb.dts

@@ -16,6 +16,7 @@
 	chosen {
 		zephyr,sram = &sram0;
 		zephyr,console = &uart0;
+		zephyr,shell-uart = &uart0;
 		zephyr,flash = &flash0;
 	};
 };