scripts/dts/extract_dts_includes.py: Cleanup yaml file finding

Cleanup how we find the yaml files for device tree bindings.  Move to a
recursive dir search of the dts/ dir.  This will be useful for
supporting re-organizing of the yaml files to match binding dir
structure.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
2 files changed