format-code: add '--no-diff' option

When running on uncommitted content, it is helpful to avoid the
output `git diff` since it is known that this will fail.  Add the
option so that users can run the script and format their whole
repository even on uncommitted content.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Iea6c8c35eb99ab0598085e0c9cfb1edff29c7690
1 file changed