We have three duplicated ADC read console command, and we are about to
have the fourth. Let's consolidate them to a single implementation in
common/.
Note that we have to add a simple implementation of
adc_read_all_channels() for LM4.
BUG=chrome-os-partner:18343
TEST=Build all boards
TEST=Read single channel
TEST=Read all channels
BRANCH=None
Change-Id: I079c0b33ab6b81a188f309cf99875eb02e9d78a4
Signed-off-by: Vic (Chun-Ju) Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/180831