run_checkpatch.sh does not report --max-line-length violation

[mshinjo]

--strcit is required when used with --file

  --max-line-length=n        set the maximum line length, (default 100)
                             if exceeded, warn on patches
                             requires --strict for use with --file

[mshinjo]

For context, run_checkpatch.sh uses --file so that a user can run checkpatch locally with ease. Otherwise, the user would need to make a Git commit (patch).