Bluetooth: btintel: Refactoring setup routine for bootloader devices

This patch refactors the setup routines for legacy and TLV based
bootloader devices to the combined setup, and move the related functions
from btusb to btintel.

Signed-off-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>