fix unused arguments to scale clip test.

TBR=kjellander@chromium.org
BUG=libyuv:680
TEST= None

Change-Id: Iae354bb5284781907569706adcf74fa2aa691997
Reviewed-on: https://chromium-review.googlesource.com/442011Reviewed-by: Frank Barchard <fbarchard@google.com>
Commit-Queue: Frank Barchard <fbarchard@google.com>