ppc4xx: remove DU405 board

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
diff --git a/doc/README.scrapyard b/doc/README.scrapyard
index 6f7598f..c650a1d 100644
--- a/doc/README.scrapyard
+++ b/doc/README.scrapyard
@@ -12,6 +12,7 @@
 
 Board            Arch        CPU            Commit      Removed     Last known maintainer/contact
 =================================================================================================
+DU405            ppc4xx      405gpr         -           -           Matthias Fuchs <matthias.fuchs@esd.eu>
 DP405            ppc4xx      405ep          -           -           Matthias Fuchs <matthias.fuchs@esd.eu>
 CPCIISER4        ppc4xx      405gp          -           -           Matthias Fuchs <matthias.fuchs@esd.eu>
 CMS700           ppc4xx      405ep          -           -           Matthias Fuchs <matthias.fuchs@esd.eu>