Bluetooth: Add scan_rsp parameter to mgmt_device_found()

In preparation for being able to merge ADV_IND/ADV_SCAN_IND and SCAN_RSP
together into a single device found event add a second parameter to the
mgmt_device_found function. For now all callers pass NULL as this
parameters since we don't yet have storing of the last received
advertising report.

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