COM audio did not tune in (voice room) if channel was already selected at startup

Reason was: hardcoded channel spacing to 8.33kHz

As a result changed to channel spacing based on COM unit, which could also be changed at runtime

* the issue itself was in own aircraft context
* added functions for channel spacing
* changed to COM unit channel spacing (instead of hardcoded spacing)

src/blackgui/components/cockpitcomcomponent.h

@@ -89,6 +89,12 @@ namespace BlackGui
             //! Update voice room related information
             void updateVoiceRoomStatusFromContext(const BlackMisc::Audio::CVoiceRoomList &selectedVoiceRooms, bool connected);
 
+            //! Update the cockpit from aircraft context
+            void forceCockpitUpdateFromOwnAircraftContext();
+
+            //! Stations changed
+            void onAtcStationsChanged();
+
             QScopedPointer<Ui::CCockpitComComponent> ui;
         };
     } // namespace