[gnome-panel] toplevel: fix -Werror=enum-conversion warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit ee97ee9e8ef6a95e1777db249bc1a6468c8aa185
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Wed Aug 26 16:43:41 2020 +0300

    toplevel: fix -Werror=enum-conversion warning

 gnome-panel/panel-toplevel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gnome-panel/panel-toplevel.c b/gnome-panel/panel-toplevel.c
index fc8c6191e..e3beaa598 100644
--- a/gnome-panel/panel-toplevel.c
+++ b/gnome-panel/panel-toplevel.c
@@ -4549,7 +4549,7 @@ panel_toplevel_set_orientation (PanelToplevel    *toplevel,
 PanelOrientation
 panel_toplevel_get_orientation (PanelToplevel *toplevel)
 {
-       g_return_val_if_fail (PANEL_IS_TOPLEVEL (toplevel), GTK_ORIENTATION_HORIZONTAL);
+       g_return_val_if_fail (PANEL_IS_TOPLEVEL (toplevel), PANEL_ORIENTATION_TOP);
 
        return toplevel->priv->orientation;
 }