mpc8260: remove PM825, PM826, PM828 board support

These boards are still non-generic boards.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Wolfgang Denk <wd@denx.de>
diff --git a/doc/README.scrapyard b/doc/README.scrapyard
index d358d62..f1c2f8b 100644
--- a/doc/README.scrapyard
+++ b/doc/README.scrapyard
@@ -12,6 +12,9 @@
 
 Board            Arch        CPU            Commit      Removed     Last known maintainer/contact
 =================================================================================================
+PM825            powerpc     mpc8260        -           -           Wolfgang Denk <wd@denx.de>
+PM826            powerpc     mpc8260        -           -           Wolfgang Denk <wd@denx.de>
+PM828            powerpc     mpc8260        -           -
 MPC8266ADS       powerpc     mpc8260        -           -           Rune Torgersen <runet@innovsys.com>
 VoVPN-GW         powerpc     mpc8260        -           -
 ep8260           powerpc     mpc8260        -           -           Frank Panno <fpanno@delphintech.com>