Qt: use qtu( ) when appropriate

Close #3333

modules/gui/qt4/components/playlist/playlist_model.cpp

@@ -854,7 +854,7 @@ void PLModel::search( const QString& search_text, const QModelIndex & idx, bool
         playlist_item_t *p_root = playlist_ItemGetById( p_playlist,
                                                         itemId( idx ) );
         assert( p_root );
-        const char *psz_name = search_text.toUtf8().data();
+        const char *psz_name = qtu( search_text );
         playlist_LiveSearchUpdate( p_playlist , p_root, psz_name, b_recursive );
 
         if( idx.isValid() )