mtd: denali: add Denali NAND driver for SPL

The SPL-mode driver for Denali(Cadence) NAND Flash Memory Controller IP.

This driver requires two CONFIG macros:
 - CONFIG_SPL_NAND_DENALI
     Define to enable this driver.
 - CONFIG_SYS_NAND_BAD_BLOCK_POS
     Specify bad block mark position in the oob space. Typically 0.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Chin Liang See <clsee@altera.com>
Cc: Scott Wood <scottwood@freescale.com>