hdctools: servod: bugfix for checking CNVR during calibration

BUG=none
TEST=manual, start servod, make sure first read to a _mw || _ma
control doesn't fail.

Change-Id: I6ca85392f1570281f1aa1c44b334c18aa9769f68
Reviewed-on: http://gerrit.chromium.org/gerrit/3487
Reviewed-by: Doug Anderson <dianders@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>
1 file changed