Make parameters match in the code to the header.

TBR=braveyao@chromium.org
Bug: libyuv:782
Test: try bots still build
Change-Id: Id53fa2fe988aee5e125d87bc5fe70cce6b275403
Reviewed-on: https://chromium-review.googlesource.com/938948Reviewed-by: Frank Barchard <fbarchard@chromium.org>