texinfo: new host package

The makeinfo program from texinfo is needed to get Crosstool-NG to
build properly a toolchain. Long term, it would be great if
Crosstool-NG supported building without texinfo, simply by disabling
the build of documentation.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>