Bluetooth: Add support setup stage internal notification event

Before the vendor specific setup stage is triggered call back into the
core to trigger an internal notification event. That event is used to
send an index update to the monitor interface. With that specific event
it is possible to update userspace with manufacturer information before
any HCI command has been executed. This is useful for early stage
debugging of vendor specific initialization sequences.

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