This adapts all files that were identifed by licensecheck
(https://salsa.debian.org/build-common-team/licensecheck.git) as
licensed under the GPL.

The advantage is that these specifiers are machine-parseable which helps
license conformance, e.g. for packaging barebox in Debian.

While touching these files also do some minor comment reformatting to
get some uniform layout.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Roland Hieber <rhi@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

The i.MX6ull-EVK is a evaluation board for the i.MX6ull from NXP.
The upstream DTS is used, support should be fairly complete:

- 2x fec ethernet
- 1x USB Host
- 1x USB OTG
- 2x SD

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>