Bluetooth: Allow mgmt_device_found events for kernel-side scanning

When the kernel is doing LE scanning because of one or more devices
added with action 0x00 through the Add Device command we do want to let
mgmt_device_found() to proceed with sending an event. This kind of
devices are tracked with hdev->pend_le_reports, so check this value
before bailing out from the function.

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