Fix lint-stable checkin hooks on MacOS X

Fix lint-stable checkin hooks on MacOS X

- wc adds a number of leading spaces which broke cut
- sed can't replace spaces with new lines, so use tr for that.
- make sure directories are created if they're not there.

Change-Id: Ia0db059683abe3d97b0ab6feaece660a1f4e5079
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/774
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)