[gimp] app: fix build warning.

[Jehan <jehanp src gnome org>]

commit 69ee9c927ba65fa18c68bbfd8dcb6c4ef12a8cf8
Author: Jehan <jehan girinstud io>
Date:   Wed Feb 2 16:20:28 2022 +0100

    app: fix build warning.

 app/widgets/gimplayertreeview.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/app/widgets/gimplayertreeview.c b/app/widgets/gimplayertreeview.c
index 93e99b9a59..9759b95da2 100644
--- a/app/widgets/gimplayertreeview.c
+++ b/app/widgets/gimplayertreeview.c
@@ -1361,7 +1361,7 @@ static void
 gimp_layer_tree_view_new_link_exit (GimpLayerTreeView *view)
 {
   if (gimp_layer_tree_view_new_link_clicked (view))
-    gtk_widget_hide (GTK_POPOVER (view->priv->link_popover));
+    gtk_widget_hide (view->priv->link_popover);
 }
 
 static gboolean