mtd: denali: use NAND_CI_CELLTYPE_MSK instead of hardcoded constant

Use NAND_CI_CELLTYPE_MSK to extract the cell type from nand_chip.cellinfo
instead of hardcoded constant.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>