CRAS: ewma_power - Fix bug in calculating power in multiple channels

BUG=b:164443860
TEST=unittest

Change-Id: Ib9c068a056f1e6c3f4b264020438f19f7e11d6a2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/2512939
Reviewed-by: Chih-Yang Hsia <paulhsia@chromium.org>
Tested-by: Hsinyu Chao <hychao@chromium.org>
Commit-Queue: Hsinyu Chao <hychao@chromium.org>
2 files changed