Making pdfdocs with sphinx - only select rst targets

[Luis R. Rodriguez]

I'm excited to see the new documentation format, so I'm changing my
documentation in the pending patches I have to use it. I however
cannot generate anything other than the main

Documentation/output/pdf/Kernel.pdf

How can I see in PDF the other documentation?

I'm using:

make DOCBOOKS="" pdfdocs

The Documentation/output/pdf/Kernel.pdf only has a bit of the
documentation on how to write docs, nothing else. Using htmldocs as a
target works but I am not a fan of that output.

  Luis