Removes macros that were part of standard basic_types
header but not used by libyuv itself.

TBR=braveyao@chromium.org
Bug: libyuv:774
Test: try bots still build
Change-Id: I8de6fad5a9277df0a50959881392ba212b1b5972
Reviewed-on: https://chromium-review.googlesource.com/879591Reviewed-by: Frank Barchard <fbarchard@chromium.org>