The cmdline is the easiest to change source of information. Thus
let it take precedence over 'RedBoot' and 'ofpart'. This makes the
mxc_nand driver to be in sync with all other NAND drivers that support
'cmdlinepart' partition parsing.

Also change 'const char *' to 'const char const *' as advised by checkpatch.pl
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>