[gtk+] GdkRenderer: Fix a compiler warning

[Timm Bäder <baedert src gnome org>]

commit 6637b20b4ced7e8ba5e555db673be801dcde57fb
Author: Timm Bäder <mail baedert org>
Date:   Sun Mar 19 14:26:02 2017 +0100

    GdkRenderer: Fix a compiler warning

 gsk/gskrenderer.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gsk/gskrenderer.c b/gsk/gskrenderer.c
index c2c2bf6..adc5040 100644
--- a/gsk/gskrenderer.c
+++ b/gsk/gskrenderer.c
@@ -798,7 +798,7 @@ get_renderer_for_display (GdkWindow *window)
   GdkDisplay *display = gdk_window_get_display (window);
   const char *renderer_name;
 
-  renderer_name = g_object_get_data (display, "gsk-renderer");
+  renderer_name = g_object_get_data (G_OBJECT (display), "gsk-renderer");
   return get_renderer_for_name (renderer_name);
 }