[mutter] input-settins/x11: Fix switch fallthrough warning

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

commit 43870a5f552ee40cee66ff7e673d5123edd72d16
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Mar 4 20:57:50 2022 +0100

    input-settins/x11: Fix switch fallthrough warning
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2319>

 src/backends/x11/meta-input-settings-x11.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/backends/x11/meta-input-settings-x11.c b/src/backends/x11/meta-input-settings-x11.c
index 858e90a5b5..0cfbb0aff3 100644
--- a/src/backends/x11/meta-input-settings-x11.c
+++ b/src/backends/x11/meta-input-settings-x11.c
@@ -593,6 +593,7 @@ set_device_accel_profile (ClutterInputDevice         *device,
       break;
     default:
       g_warn_if_reached ();
+      G_GNUC_FALLTHROUGH;
     case G_DESKTOP_POINTER_ACCEL_PROFILE_DEFAULT:
       values[0] = defaults[0];
       values[1] = defaults[1];