boards: arm: stm32f411e_disco: Add MCUmgr UART chosen node

Adds a chosen node for MCUmgr UART

Signed-off-by: Jamie McCrae <[email protected]>

Author: nordicjm

boards/arm/stm32f411e_disco/stm32f411e_disco.dts

@@ -16,6 +16,7 @@
 	chosen {
 		zephyr,console = &usart2;
 		zephyr,shell-uart = &usart2;
+		zephyr,uart-mcumgr = &usart2;
 		zephyr,sram = &sram0;
 		zephyr,flash = &flash0;
 		zephyr,code-partition = &slot0_partition;