media/gpu/vaapi/vaapiVEA: Enable vaapiVEA to encode NV12 input buffers

In Chromium, intel devices allocates NV12 VASurface.
VaapiVEA only accepts I420 input buffers for video encoding. It converts the
buffers to NV12 and copies to VA Surfaces.
This enables vaapiVEA to accept NV12 input buffers. It just copies the input
buffers to VA Surfaces without any conversion since their formats are same.

BUG=894381
TEST=VEA unittest with NV12 input buffer on eve

Change-Id: I83a53603a15c0eaa787c1b66cccbd8a2fcc48c18
Reviewed-on: https://chromium-review.googlesource.com/c/1293254
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602609}
2 files changed