[autotest] audio_AudioBasicInternalMicrophone: Loose the test

Set second_peak_ratio to 0.2 to tolerate sound reflection in the box.

BUG=chromium:561212
TEST=run the test on auron_paine and squawks.

Change-Id: I3a273403e87591e7b3979d720008e32f0f79d154
Reviewed-on: https://chromium-review.googlesource.com/313899
Commit-Ready: Cheng-Yi Chiang <cychiang@chromium.org>
Tested-by: Cheng-Yi Chiang <cychiang@chromium.org>
Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>
1 file changed