buildtools: build with meson

buildtools: build with meson

Add the buildtools folder, and more specifically the pmdinfogen binary to
the meson and ninja build. This will be needed for building the PMDs in the
driver folder later, as the pmd info output from the tool needs to be
included in those libs.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: Keith Wiles <keith.wiles@intel.com>
Acked-by: Luca Boccassi <luca.boccassi@gmail.com>