[babl] babl: silence cast warning

[Øyvind Kolås <ok src gnome org>]

commit 3c230ba16802a37a8285719ba83bd9be42f13a60
Author: Øyvind Kolås <pippin gimp org>
Date:   Wed Aug 30 16:38:05 2017 +0200

    babl: silence cast warning

 babl/babl-format.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/babl/babl-format.c b/babl/babl-format.c
index ebf51db..4ed14d0 100644
--- a/babl/babl-format.c
+++ b/babl/babl-format.c
@@ -737,7 +737,7 @@ babl_format_with_space (const char *name, const Babl *space)
       return ret;
 
     ret = format_new_from_format_with_space (babl_format (name), space);
-    babl_db_insert (db, ret);
+    babl_db_insert (db, (void*)ret);
   }
   return ret;
 }