samples: smp_svr: use new USB device stack

Use new USB device stack.

Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>

Author: jfischer-no

samples/subsys/mgmt/mcumgr/smp_svr/overlay-cdc.conf

@@ -1,9 +1,9 @@
 # Enable USB subsystem
-CONFIG_USB_DEVICE_STACK=y
 CONFIG_SERIAL=y
 CONFIG_UART_LINE_CTRL=y
-CONFIG_USB_DEVICE_INITIALIZE_AT_BOOT=n
 CONFIG_CONSOLE=y
+CONFIG_USB_DEVICE_STACK_NEXT=y
+CONFIG_CDC_ACM_SERIAL_INITIALIZE_AT_BOOT=y
 # USB backend is serial device
 CONFIG_MCUMGR_TRANSPORT_UART=y
 CONFIG_BASE64=y

samples/subsys/mgmt/mcumgr/smp_svr/src/main.c

@@ -71,15 +71,6 @@ int main(void)
 	start_smp_bluetooth_adverts();
 #endif
 
-	if (IS_ENABLED(CONFIG_USB_DEVICE_STACK)) {
-		rc = usb_enable(NULL);
-
-		/* Ignore EALREADY error as USB CDC is likely already initialised */
-		if (rc != 0 && rc != -EALREADY) {
-			LOG_ERR("Failed to enable USB");
-			return 0;
-		}
-	}
 	/* using __TIME__ ensure that a new binary will be built on every
 	 * compile which is convenient when testing firmware upgrade.
 	 */