PRESUBMIT.cfg: Lint commits, not files

`cros lint` has a semi-new feature to check the contents as they exist
in git, which makes linting stacks of commits better.

Rename the hook while we're at it, to give nicer output when it's run.

Borrowed from platform2/PRESUBMIT.cfg.

BUG=none
TEST=`repo upload`

Change-Id: I0d8416356d0e19b053e5aa4c943e4727e1e6c4af
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/moblab/+/5191667
Commit-Queue: Varun Thammineni <varunth@google.com>
Tested-by: Varun Thammineni <varunth@google.com>
Reviewed-by: Varun Thammineni <varunth@google.com>
Tested-by: Brian Norris <briannorris@chromium.org>
1 file changed