powerpc: ppc4xx: remove korat board support

This has not been converted to Generic Board, so should be removed.
(See doc/README.generic-board for details.)

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Larry Johnson <lrj@acm.org>
diff --git a/doc/README.scrapyard b/doc/README.scrapyard
index 1f2320b..59d2142 100644
--- a/doc/README.scrapyard
+++ b/doc/README.scrapyard
@@ -12,6 +12,7 @@
 
 Board            Arch        CPU            Commit      Removed     Last known maintainer/contact
 =================================================================================================
+korat            powerpc     ppc4xx         -           -           Larry Johnson <lrj@acm.org>
 galaxy5200       powerpc     mpc5xxx        -           -           Eric Millbrandt <emillbrandt@dekaresearch.com>
 W7OLMC           powerpc     ppc4xx         -           -           Erik Theisen <etheisen@mindspring.com>
 W7OLMG           powerpc     ppc4xx         -           -           Erik Theisen <etheisen@mindspring.com>