QmlProfiler: Don't double-insert pixmap end events

If the pixmap started loading before the trace started we already do
insert(...) a few lines above, which includes inserting the end.

Change-Id: Idce0aca84f1c935fc2d4614b758e1575dde59a40
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/qmlprofiler/pixmapcachemodel.cpp

@@ -349,9 +349,10 @@ void PixmapCacheModel::loadEvent(const QmlEvent &event, const QmlEventType &type
                     }
                 }
             }
+        } else {
+            insertEnd(state.started, pixmapStartTime - startTime(state.started));
         }
 
-        insertEnd(state.started, pixmapStartTime - startTime(state.started));
         if (pixmapType == PixmapLoadingError) {
             state.loadState = Error;
             switch (state.cacheState) {