This isn't a common license as it's the DocBook v4 XML DTD license, and
that is now part of the recipe itself.
(From OE-Core rev: 11c366ebff98dad34d95aac0cfee571f78b87252)
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>