Add missing EFIAPI modifiers to the functions that are exposed via the
PCI I/O protocol.
At the same time, add a missing UINT8 cast which breaks the build on
Visual Studio.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Dandan Bi <dandan.bi@intel.com>