efl_canvas: fix a potentional error of null deref

this is a patch to fix a potentional error by null dereferencing.

Reviewed-by: Marcel Hollerbach <mail@marcel-hollerbach.de>
Differential Revision: https://phab.enlightenment.org/D12093

src/lib/efl_canvas_wl/efl_canvas_wl.c

@@ -4170,6 +4170,7 @@ static void
 comp_render_pre_proxied(Eo *o, Evas *e, void *event_info)
 {
    Comp_Surface *cs = evas_object_data_get(o, "comp_surface");
+   EINA_SAFETY_ON_NULL_RETURN(cs);
    Comp_Buffer *buffer = cs->buffer[!cs->render_queue];
 
    //fprintf(stderr, "PROXY RENDER_PRE %d\n", buffer ? wl_resource_get_id(buffer->res) : -1);