[gnome-control-center] universal-access: Fix compile warning

[Robert Ancell <rancell src gnome org>]

commit a760707291eb395f45e53edf126a4a6d2ef24ae3
Author: Robert Ancell <robert ancell canonical com>
Date:   Tue Aug 13 10:40:14 2019 +1200

    universal-access: Fix compile warning
    
    Introduced in 38897a751b

 panels/universal-access/cc-ua-panel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/panels/universal-access/cc-ua-panel.c b/panels/universal-access/cc-ua-panel.c
index ef55c5486..aebdd572b 100644
--- a/panels/universal-access/cc-ua-panel.c
+++ b/panels/universal-access/cc-ua-panel.c
@@ -203,7 +203,7 @@ cc_ua_panel_dispose (GObject *object)
 {
   CcUaPanel *self = CC_UA_PANEL (object);
 
-  g_clear_pointer (&self->zoom_options, gtk_widget_destroy);
+  g_clear_pointer ((GtkWidget **)&self->zoom_options, gtk_widget_destroy);
   g_slist_free_full (self->toplevels, (GDestroyNotify)gtk_widget_destroy);
   self->toplevels = NULL;