mpc8xx: remove netta, netta2, netphone board support

These boards are old enough and have no maintainers.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/doc/README.scrapyard b/doc/README.scrapyard
index fe666a5..c28bb52 100644
--- a/doc/README.scrapyard
+++ b/doc/README.scrapyard
@@ -11,6 +11,9 @@
 
 Board            Arch        CPU            Commit      Removed     Last known maintainer/contact
 =================================================================================================
+netphone         powerpc     mpc8xx         -           -
+netta2           powerpc     mpc8xx         -           -
+netta            powerpc     mpc8xx         -           -
 rbc823           powerpc     mpc8xx         -           -
 quantum          powerpc     mpc8xx         -           -
 RPXlite_dw       powerpc     mpc8xx         -           -