mosys: Increase part number string size.

BUG=b:120000816
TEST=None

Change-Id: I586c2ab485a2a28463b9b95f3af2784d4d4fb60a
Reviewed-on: https://chromium-review.googlesource.com/1365855
Commit-Ready: Cheng-Han Yang <chenghan@chromium.org>
Tested-by: Jack Huang <jachuang@chromium.org>
Reviewed-by: Martin Roth <martinroth@chromium.org>
1 file changed