servod: fix bug reporting command line parameters mismatch

There is no need to report a problem if the command line parameter
matches the config file value. But if there is a mismatch, let's use
the servo serial number to identify which servo the message is for.

BRANCH=none
BUG=none
TEST=passing -b on the command line when the config file is used does
     not cause a failure anymore. If the command line parameter does
     not agree with the config file, a proper message is printed:

     $ grep storm /home/vbendeb/.servodrc
     storm, 686203-00062, 9900, storm
     $ servod -b storm  # succeeds
     $ servod -b daisy
     ...
     2015-03-25 13:09:13,877 - servod.py - WARNING - Ignoring rc configured board name storm for servo 686203-00062
     ...

Change-Id: I92339eed0707decbf5b6b0040437308aca9346fd
Reviewed-on: https://chromium-review.googlesource.com/262452
Tested-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>
Commit-Queue: Vadim Bendebury <vbendeb@chromium.org>
1 file changed