[gegl] saturation: add default case to switch heeding warning from gcc

[Øyvind "pippin" Kolås <ok src gnome org>]

commit eecdf9d07cb1d095fc6dfe3b0fec02002311b52b
Author: Øyvind Kolås <pippin gimp org>
Date:   Mon Jul 8 12:28:35 2019 +0200

    saturation: add default case to switch heeding warning from gcc

 operations/common/saturation.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/operations/common/saturation.c b/operations/common/saturation.c
index 4c5ebc44d..0af283051 100644
--- a/operations/common/saturation.c
+++ b/operations/common/saturation.c
@@ -228,6 +228,7 @@ static void prepare (GeglOperation *operation)
 
   switch (o->colorspace)
   {
+    default:
     case GEGL_SATURATION_TYPE_NATIVE:
       format = babl_format_with_space ("RGBA float", space);
       o->user_data = process_rgb_alpha;