Fix dxva_video_decode_accelerator.cc to compile with Win 10 SDK

dxva_video_decode_accelerator.cc defines CLSID_VideoProcessorMFT,
and so does mfidl.h in the Windows 10 SDK. This change uses
VER_PRODUCTBUILD to detect the SDK version so that this source
file can build with the Windows 8.1 and Windows 10 SDKs.

R=dalecurtis@chromium.org
BUG=491424

Review URL: https://codereview.chromium.org/1244883002

Cr-Commit-Position: refs/heads/master@{#339505}