treewide: remove references to CREDITS ...

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>

ARM: samsung: make locally used function static ...

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

ARM: samsung: remove unused function ...

s3c24_get_uclk() is unused, remove it.

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

ARM/Samsung: follow the name style of the other source files in this directory ...

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