boards: clean up CDC ACM configuration for nRF52840 based boards

Remove CDC ACM UART devicetree nodes, chosen properties and explicit
USB support configuration in favor of generic CDC ACM shield.
For console support via USB CDC ACM, in-tree samples for this boards
is to be built as follows:

west build -b nrf52840dongle_nrf52840
  samples/basic/threads -- -DSHIELD=cdc_acm_console

For shell support via USB CDC ACM, in-tree samples for this boards
is to be built as follows:

west build -b nrf52840dongle_nrf52840
  samples/subsys/shell/shell_module -- -DSHIELD=cdc_acm_shell

Signed-off-by: Johann Fischer <[email protected]>

Author: jfischer-no

boards/arm/degu_evk/Kconfig.defconfig

@@ -8,19 +8,6 @@ if BOARD_DEGU_EVK
 config BOARD
 	default "degu_evk"
 
-if USB_DEVICE_STACK
-
-config USB_DEVICE_PRODUCT
-	default "Degu Evaluation Kit"
-
-config UART_INTERRUPT_DRIVEN
-	default y
-
-config UART_LINE_CTRL
-	default y
-
-endif # USB_DEVICE_STACK
-
 if DISK_DRIVER_FLASH
 
 config DISK_FLASH_DEV_NAME

boards/arm/degu_evk/degu_evk.dts

@@ -15,8 +15,8 @@
 	chosen {
 		zephyr,sram = &sram0;
 		zephyr,flash = &flash0;
-		zephyr,console = &degu_cdc_acm_uart;
-		zephyr,shell-uart = &degu_cdc_acm_uart;
+		zephyr,console = &uart0;
+		zephyr,shell-uart = &uart0;
 		zephyr,code-partition = &slot0_partition;
 		zephyr,ieee802154 = &ieee802154;
 	};
@@ -161,8 +161,4 @@
 zephyr_udc0: &usbd {
 	compatible = "nordic,nrf-usbd";
 	status = "okay";
-
-	degu_cdc_acm_uart: degu_cdc_acm_uart {
-		compatible = "zephyr,cdc-acm-uart";
-	};
 };

boards/arm/degu_evk/degu_evk_defconfig

@@ -12,9 +12,6 @@ CONFIG_SERIAL=y
 CONFIG_CONSOLE=y
 CONFIG_UART_CONSOLE=y
 
-# enable USB (for CDC ACM console)
-CONFIG_USB_DEVICE_STACK=y
-
 # additional board options
 CONFIG_GPIO=y
 CONFIG_GPIO_AS_PINRESET=y

boards/arm/nrf52840dongle_nrf52840/Kconfig.defconfig

@@ -24,14 +24,6 @@ config FLASH_LOAD_OFFSET
 	default 0x1000
 	depends on BOARD_HAS_NRF5_BOOTLOADER && !USE_DT_CODE_PARTITION
 
-if USB_DEVICE_STACK
-
-# Enable UART driver, needed for CDC ACM
-config SERIAL
-	default y
-
-endif # USB_DEVICE_STACK
-
 config BT_CTLR
 	default BT