Bluetooth: Mark controller is down when HCI_AUTO_OFF is set

During the initial setup phase, the controller is powered on and will
be powered off again if it is not used within the auto-off timeout.

Userspace using ioctl does not know about the difference between the
initial setup phase and a controller being present. It is a bad idea
to keep the controller powered by just looking at the device list or
device information. Instead just tell userspace that the controller
is still down.

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