UCM: veyron - set min buffer level on HDMI

Because of the lack of a residue function on veyron we need to pad the
output buffer by an extra 512 frames so it doesn't underrun.

BUG=chromium:560426
TEST=run audio_AudioBasicHDMI test on veyron_jerry

Change-Id: I0e7c8c97453e0406d50215eb6ae76a9b61b0b1ce
Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/330036
Reviewed-by: Dylan Reid <dgreid@chromium.org>
4 files changed