guybrush: Enable bit-bang dev beep

Enable bit-bang dev beep for the second source speaker amp MAX98360.

BUG=b:191713025
BRANCH=none
TEST=Tested on alc1019

Signed-off-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Change-Id: Ia3221317907946acbbbd748768ccbe5e790cdfff
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/depthcharge/+/3029464


Reviewed-by: Karthikeyan Ramasubramanian <kramasub@chromium.org>