OvmfPkg: IndustryStandard: add definitions from the VirtIo 1.0 spec
    
    These header files are intentionally minimal, and intentionally kept apart
    from the VirtIo 0.9.5 headers.
    
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Jordan Justen <jordan.l.justen@intel.com>
    Contributed-under: TianoCore Contribution Agreement 1.0
    Signed-off-by: Laszlo Ersek <lersek@redhat.com>