Bluetooth: Add missing COMPATIBLE_IOCTL for UART line discipline

The HCIUARTGETDEVICE, HCIUARTSETFLAGS and HCIUARTGETFLAGS ioctl are
missing the COMPATIBLE_IOCTL declaration.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>