efl_ui_position_manager_list: require cache here

the cache need to be required here, as we are going to access it later
on.

Reviewed-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Differential Revision: https://phab.enlightenment.org/D9823

src/lib/elementary/efl_ui_position_manager_list.c

@@ -290,6 +290,8 @@ position_content(Eo *obj EINA_UNUSED, Efl_Ui_Position_Manager_List_Data *pd)
    if (!pd->size) return;
    if (pd->average_item_size <= 0) return;
 
+   cache_require(obj, pd);
+
    //space size contains the amount of space that is outside the viewport (either to the top or to the left)
    space_size.w = (MAX(pd->abs_size.w - pd->viewport.w, 0))*pd->scroll_position.x;
    space_size.h = (MAX(pd->abs_size.h - pd->viewport.h, 0))*pd->scroll_position.y;