iwlwifi: mvm: remove d0i3 ref correctly during AP start

The AP_START d0i3 reference was never removed if the AP started correctly.
This has the unpleasant side-effect of preventing D0i3 on Android if the
WiFi hotspot was ever started on the device.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>