Remove plan9 related stuff as they are useless for linux systems.
(From OE-Core rev: f0f11d868bbf02ffc8352e77c075de0577c2746e)
Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>