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>

cmdlinepart: Allow empty string ...

Currently when cmdlinepart_do_parse() is called with an empty
partitions string then an unnamed partition with size 0 is created.
This is wrong of course and instead no partition should be
created.

With this barebox no longer crashes while booting when all partitions
are deleted on the commandline using "nand0.partitions="

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

cmndlinepart: skip devname if partstr already contains it ...

When the partition name already starts with "devname." skip this
when adding the partition.

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

cmdlinepart: add function to parse a cmdline partition string ...

This adds a function to parse a full cmdline partition string. The
addpart command is switched to use this function.

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

cmdlinepart: make argument types safer ...

The return size should be loff_t to support partitions bigger
than 4G. Also use const for the devname and endp.

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

cmdlinepart: Change SIZE_REMAINING to loff_t ...

For compatibility with devices > 4G.

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

move cmdline partition parsing code to separate file ...

So it's no longer local to the addpart/delpart code and can be used
from other code.

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