Adopt the SPDX license identifier headers to ease license compliance
management.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>