usb: cdc_acm: use same init level and priority as serial drivers

Use same init level and priority as serial drivers.
Align priority to the changes in
commit ad14505 ("drivers: serial: Refactor drivers
to use shared init priority Kconfig")

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

Author: jfischer-no

subsys/usb/class/cdc_acm.c

@@ -1104,7 +1104,7 @@ static const struct uart_driver_api cdc_acm_driver_api = {
 									\
 	DEVICE_DT_INST_DEFINE(idx, cdc_acm_init, NULL,			\
 		&cdc_acm_dev_data_##idx, &cdc_acm_config_##idx,		\
-		POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,	\
+		PRE_KERNEL_1, CONFIG_SERIAL_INIT_PRIORITY,		\
 		&cdc_acm_driver_api);
 
 DT_INST_FOREACH_STATUS_OKAY(CDC_ACM_DT_DEVICE_DEFINE);