Bluetooth: Use real advertising state to random address update decision

Now that we have a flag for tracking the real advertising state we
should use that to determine whether it's safe to update the random
address or not. The couple of places that were clearing the flag due to
a pending request need to be updated too.

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