Put in a cross-reference to the section in the sdk-manual where it
talks about customizing the configuration of the extensible SDK.
(From yocto-docs rev: 23e4a2d0f461a8c672aa3780965ca4e30d1aac50)
Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>