sunxi: nand: Add board configuration options

When SPL_NAND_SUNXI option is selected in config, set some configuration
options for sunxi NAND.

This commit also introduces the configurable options in Kconfig.

Signed-off-by: Peter Gielda <pgielda@antmicro.com>
Signed-off-by: Tomasz Gorochowik <tgorochowik@antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
Signed-off-by: Piotr Zierhoffer <pzierhoffer@antmicro.com>
Signed-off-by: Karol Gugala <kgugala@antmicro.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>