mtd: atmel_nand: replace memcpy32_toio/memcpy32_fromio with memcpy

There is no need to use memcpy32_toio/memcpy32_fromio to transfer data
between memory and NFC sram. As the NFC sram is a also a memory space
not an I/O space, we can just use memcpy().

We remove the __iomem prefix for NFC sram to avoid sparse warnings.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Reviewed-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>