mtd: nand: denali: use int where no reason to use fixed width variable

The page number is generally stored in an integer type variable.
The uint16_t does not have enough width.  I see no reason to use
uint32_t for other members, either.  Just use int.

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