mtd: nand: denali: support two row address cycle devices

The register TWO_ROW_ADDR_CYCLES specifies the number of row address
cycles of the device, but it is fixed to 0 in the driver init code
(i.e. always 3 row address cycles).

Reflect the result of nand_scan_ident() to the register setting
in order to support 2 row address cycle devices.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>