tools: Add cleanpatch

There are some errors reported by checkpatch.pl that can be easily cleaned up by
using the cleanpatch tool.

Import the cleanpatch script from linux kernel 3.5.4 stable version as from the
following commit:

commit cb3ed5b7e09c6c0462e396d55e3fecc0980a333a
Author: H. Peter Anvin <hpa@zytor.com>
Date:   Fri May 25 17:58:26 2007 -0700

    scripts: Make cleanfile/cleanpatch warn about long lines

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>