The CREDITS file was removed from barebox in 2015 by commit 6570288f2d97
("Remove the CREDITS file"). Remove references to it from several files.

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

Of_unflatten_dtb returns a ERR_PTR value so checking it against NULL is
incorrect. Fix it in all of the places where this was happening.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Cc: Franck Jullien <franck.jullien@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>