It is needed for k2l keystone2 EVM which uses NAND flash with 4K page
size, hence add support for 4K page size nand devices.

[Brian: similar work submitted by Murali Karicheri <m-karicheri2@ti.com>
and Hao Zhang <hzhang@ti.com>]
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>