[yocto] Build error while following Appendix A. Yocto Project Development manual

[Jim Abernathy]

Well, I finally got a "successful" build without erros of the Appendix A
example for Crownbay, but the image created was only 216MB in size and
kernel panic'ed because it couldn't find a valid root file system.

I'm going to try again from scratch and see if I missed anything. If
that fails, I'll report out.

Jim A