misc: qemu_vfat: Add support to build with waf

* Add a wscript file, but it isn't added to misc/wscript as
  qemu_vfat doesn't build for all platforms even with make

TODO: Invetigate more and find a proper fix
Merge pull request #17 from chirayudesai/waf/qemu_vfat

misc: qemu_vfat: Add support to build with waf