arm: Remove support for smdk6400

The migration of boards from Makefile to boards.cfg was due for v2012.03, but
smdk6400 did not follow, and it does not build, so move it to scrapyard. It will
still be possible to restore it from the Git history before fixing it.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
diff --git a/doc/README.scrapyard b/doc/README.scrapyard
index 189b883..2cdb8a9 100644
--- a/doc/README.scrapyard
+++ b/doc/README.scrapyard
@@ -11,6 +11,7 @@
 
 Board            Arch        CPU            Commit      Removed     Last known maintainer/contact
 =================================================================================================
+smdk6400         arm         arm1176        -           -           Zhong Hongbo <bocui107@gmail.com>
 ns9750dev        arm         arm926ejs      -           -           Markus Pietrek <mpietrek@fsforth.de>
 AMX860           powerpc     mpc860         1b0757e     2012-10-28  Wolfgang Denk <wd@denx.de>
 c2mon            powerpc     mpc855         1b0757e     2012-10-28  Wolfgang Denk <wd@denx.de>