Linux-Libre build configs

[Ludovic Courtès]

Hello!

Commit a94546e adds kernel configs for i686 and x86_64 that Jason has
been maintaining for some time (thanks!).  These configs build lots of
things as modules, as we’d expect.

I was hoping we could come up with a way to generate a kernel config,
either based on ‘allmodconfig’ or something like what NixOS does [0],
but I’ve become pretty convinced that this would be difficult at best.

Hopefully, we’ve now found our kernel config maintainer.  :-)

Ludo’.