buildtools-tarball: Add texinfo (for makeinfo)

buildtools-tarball: Add texinfo (for makeinfo)

Initially I was reluctant to do this however makeinfo is a dependency
of the buildsystem and only adds around 400kb to the buildtools-tarball
so it likely makes sense to add it. This allows people to use
the project on older environments.

Need to enable nativesdk-texinfo but this seems straightforward.

[YOCTO #8990]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>