[mutter] backends/x11: Don't leak XRRGetPanning result

[Marge Bot <marge-bot src gnome org>]

commit e77e454d3424091cbd0c892fa108196f0a440308
Author: Sebastian Keller <skeller gnome org>
Date:   Thu Feb 11 15:52:28 2021 +0100

    backends/x11: Don't leak XRRGetPanning result
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1728>

 src/backends/x11/meta-crtc-xrandr.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/backends/x11/meta-crtc-xrandr.c b/src/backends/x11/meta-crtc-xrandr.c
index 9f60a0d505..e06448b6e9 100644
--- a/src/backends/x11/meta-crtc-xrandr.c
+++ b/src/backends/x11/meta-crtc-xrandr.c
@@ -271,6 +271,7 @@ meta_crtc_xrandr_new (MetaGpuXrandr      *gpu_xrandr,
         .height = xrandr_crtc->height,
       };
     }
+  XRRFreePanning (panning);
 
   modes = meta_gpu_get_modes (gpu);
   for (i = 0; i < (unsigned int) resources->nmode; i++)