Bluetooth: btusb: Add setup callback for chip init on USB

Some of chipset does not allow to send a patch or config files through
HCI VS channel at early stage as well as they don't support to send
USB patch files to other channel except USB bulk path.

New callback added is for initialization of BT controller through USB

Signed-off-by: Ben Young Tae Kim <ytkim@qca.qualcomm.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>