Disable serial console output.

Because enabling the serial output would make DUT overheat in run-in
thermal test, we disable it to resolve it.

BUG=none
TEST=run run-in test in Arkham device

Change-Id: I425309e4534e891b2b8e0dafc33cde0d95477935
Reviewed-on: https://chromium-review.googlesource.com/300856
Reviewed-by: Chih-Yu Huang <akahuang@chromium.org>
Commit-Queue: Chih-Yu Huang <akahuang@chromium.org>
Tested-by: Chih-Yu Huang <akahuang@chromium.org>
1 file changed