When combining an SPDX document, the package list might be empty (e.g.
a baremetal image). Handle this case instead of erroring out
(From OE-Core rev: 1f7326799c33d2a734c58d360773b87d7b86b0ec)
Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>