create-spdx-{2.2,3.0}: fix do_create_spdx dependency while spdx include sources

create-spdx-{2.2,3.0}: fix do_create_spdx dependency while spdx include sources

Call function ${@create_spdx_source_deps(d)} or ${create_spdx_source_deps(d)}
along with addtask not working, use task do_create_spdx flag 'depends'
to instead

Move function create_spdx_source_deps to spdx-common.bbclass for both of
create-spdx-2.2.bbclass and create-spdx-3.0.bbclass

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Reviewed-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>