mtd: denali: add a DT driver

Add a device tree version of the Denali NAND driver. Based
on an original patch from Jamie Iles to add a MMIO version
of this driver.

Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>