mtd: nand: Samsung MLC - new OOB sizes

There are some additions to the detection scheme used by Samsung
MLC NAND. These simple changes to support the 400- and 436-byte OOB
are found in the following data sheet:

Samsung K9GBG08U0M (p.40)

Signed-off-by: Brian Norris <norris@broadcom.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>