create-spdx.bbclass: Remove an unnecessary path from do_create_spdx[dirs]
There is no reason to include a path in foo[dirs] if it is also in
foo[cleandirs] (except if it is the last path in foo[dirs]).
(From OE-Core rev: cb30a6cfa58072bbf5f5def36103fbcac920e168)
Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>