mtd: nand: increase max OOB size to 640

Some Hynix and Samsung MLC NAND have 640B OOB size. Sooner or later, we should
dynamically allocate the buffers that use these macros.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

include/linux/mtd/nand.h

@@ -56,7 +56,7 @@ extern int nand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
  * is supported now. If you add a chip with bigger oobsize/page
  * adjust this accordingly.
  */
-#define NAND_MAX_OOBSIZE	576
+#define NAND_MAX_OOBSIZE	640
 #define NAND_MAX_PAGESIZE	8192
 
 /*