onenand: Replace ONENAND_IS_MLC() with ONENAND_HAS_4KB()

onenand: Replace ONENAND_IS_MLC() with ONENAND_HAS_4KB()

This replacement causes 4KB page size devices to work properly with u-boot.

The old ONENAND_IS_MLC() behavior has been preserved by explicit
setting of ONENAND_HAS_4KB_PAGE for those devices.

This change makes the onenand_base.c file more resembling the respective
kernel sources.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
Test HW:
       - Samsung S5PC110 GONI
       - Samsung S5PC210 Universal