[gimp] app: fix gimp_brush_mipmap_get_memsize()

[Ell <ell src gnome org>]

commit 30e925065f1593d2ae0d8f3def6c6684c261aa81
Author: Ell <ell_se yahoo com>
Date:   Thu Feb 13 16:53:03 2020 +0200

    app: fix gimp_brush_mipmap_get_memsize()
    
    Don't include the main mask/pixmap buffer size -- it's already
    counted in gimp_brush_get_memsize().

 app/core/gimpbrush-mipmap.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/app/core/gimpbrush-mipmap.cc b/app/core/gimpbrush-mipmap.cc
index 944df4ff16..ae394dc3e9 100644
--- a/app/core/gimpbrush-mipmap.cc
+++ b/app/core/gimpbrush-mipmap.cc
@@ -483,7 +483,7 @@ gimp_brush_mipmap_get_memsize (GimpBrush *brush)
     {
       gint i;
 
-      for (i = 0;
+      for (i = 1;
            i < brush->priv->n_horz_mipmaps * brush->priv->n_vert_mipmaps;
            i++)
         {
@@ -495,7 +495,7 @@ gimp_brush_mipmap_get_memsize (GimpBrush *brush)
     {
       gint i;
 
-      for (i = 0;
+      for (i = 1;
            i < brush->priv->n_horz_mipmaps * brush->priv->n_vert_mipmaps;
            i++)
         {