samples: Bluetooth: hci_usb: Disable USB_CDC_ACM

BlueZ btusb does not recognize hci_usb sample as Bluetooth
Controller when CDC ACM is enabled in the sample.

Refer to https://github.com/zephyrproject-rtos/zephyr/issues/29107



Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>