[mutter] input-settings/native: Fix switch fallthrough warning

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

commit 339c315ed9af93855f85adf4a940e45eb83decc0
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Mar 4 20:59:35 2022 +0100

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

 src/backends/native/meta-input-settings-native.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/backends/native/meta-input-settings-native.c 
b/src/backends/native/meta-input-settings-native.c
index 8f61b8bcc4..b3fc8df8a8 100644
--- a/src/backends/native/meta-input-settings-native.c
+++ b/src/backends/native/meta-input-settings-native.c
@@ -526,6 +526,7 @@ set_device_accel_profile (ClutterInputDevice         *device,
       break;
     default:
       g_warn_if_reached ();
+      G_GNUC_FALLTHROUGH;
     case G_DESKTOP_POINTER_ACCEL_PROFILE_DEFAULT:
       libinput_profile =
         libinput_device_config_accel_get_default_profile (libinput_device);