style: catch trailing white spaces in make and dts files

Change-Id: I2a4f1893919660e51599902b972a6f3f5717e305
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

style: Move the last bits of file_types.py to the style package

The commit that refactored the style checkers into a new Python
package (style: Refactor the style checker as a Python package)
accidentally left a fragment of file_types.py in the old location
(util/style.py). This was caused by a race between the commit that
moved the file and Nate's commit that added a copyright header to the
file.

This commit moves the last fragment (the copyright header) and removes
the old file.

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>

style: Refactor the style checker as a Python package

Refactor the style checker into a Python module that can be reused by
command line tools that integrate with git. In particular:

* Create a style package in util
* Move style validators from style.py to the style/validators.py.
* Move style verifiers from style.py to the style/verifiers.py.
* Move utility functions (sort_includes, region handling,
file_types) into the style package
* Move generic code from style.py to style/style.py.

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Steve Reinhardt <steve.reinhardt@amd.com>