Bluetooth: Reject enabling controllers without valid addresses

In case of a single mode LE-only controller it is possible that no
public address is used. These type of controllers require a random
address to be configured.

Without a configured static random address, such a controller is
not functional. So reject powering on the controller in this case
until it gets configured with a random address.

The controller setup stage is still run since it is the only way
to determinate if a public address is available or not. So it is
similar on how RFKILL gets handled during initial setup of the
controller.

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