doc: Remove the obsolete README.AMCC-eval-boards-cleanup file

The related boards have been removed four years ago already, in
commit 98f705c9 ("powerpc: remove 4xx support"), so this README
file is not required anymore.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Stefan Roese <sr@denx.de>

doc/README.AMCC-eval-boards-cleanup

----------------------------------------------------------------------
-Cleanup of AMCC eval boards (Walnut/Sycamore, Bubinga, Ebony, Ocotea)
----------------------------------------------------------------------
-
-Changes to all AMCC eval boards:
---------------------------------
-
-o Changed u-boot image size to 256 kBytes instead of 512 kBytes on most
-  boards.
-
-o Use 115200 baud as default console baudrate.
-
-o Added config option to use redundant environment in flash. This is also
-  the default setting. Option for environment in nvram is still available
-  for backward compatibility.
-
-o Merged board specific flash drivers to common flash driver:
-  board/amcc/common/flash.c
-
-
-Sycamore/Walnut (one port supporting both eval boards):
--------------------------------------------------------
-
-o Cleanup to allow easier "cloning" for different (custom) boards:
-
-  o Moved EBC configuration from board specific asm-file "init.S"
-    using defines in board configuration file. No board specific
-    asm file needed anymore.
-
-
-August 01 2005, Stefan Roese <sr@denx.de>