Graphicsview: Simplify code

order is either Ascending or Descending (0 or 1), so this comparison is
unnecessary.

Change-Id: Ieceacf18f1bf3c7a7555205a140b738daa92bd04
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>

src/widgets/graphicsview/qgraphicsscenebsptreeindex.cpp

@@ -567,10 +567,7 @@ QList<QGraphicsItem *> QGraphicsSceneBspTreeIndex::items(Qt::SortOrder order) co
                 itemList << item;
         }
     }
-    if (order != -1) {
-        //We sort descending order
     d->sortItems(&itemList, order, d->sortCacheEnabled);
-    }
     return itemList;
 }