[gnome-flashback] input-settings: fix cast-function-type warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 403a5a41a16ea82df431ece612ca630ce22dff5c
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Sep 9 00:47:56 2018 +0300

    input-settings: fix cast-function-type warning

 gnome-flashback/libinput-settings/gf-input-settings.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
---
diff --git a/gnome-flashback/libinput-settings/gf-input-settings.c 
b/gnome-flashback/libinput-settings/gf-input-settings.c
index 590cb93..bcb41ad 100644
--- a/gnome-flashback/libinput-settings/gf-input-settings.c
+++ b/gnome-flashback/libinput-settings/gf-input-settings.c
@@ -1219,6 +1219,13 @@ mapped_device_changed_cb (GSettings         *gsettings,
     update_device_display (info->settings, gsettings, info->device);
 }
 
+static void
+free_device_mapping_info (gpointer  data,
+                          GClosure *closure)
+{
+  g_free (data);
+}
+
 static void
 check_add_mappable_device (GfInputSettings *settings,
                            GdkDevice       *device)
@@ -1239,7 +1246,7 @@ check_add_mappable_device (GfInputSettings *settings,
 
   g_signal_connect_data (gsettings, "changed",
                          G_CALLBACK (mapped_device_changed_cb),
-                         info, (GClosureNotify) g_free, 0);
+                         info, free_device_mapping_info, 0);
 
   g_hash_table_insert (settings->mappable_devices, device, gsettings);
   update_device_display (settings, gsettings, device);