nand: sunxi: Add options for the SPL NAND configuration

nand: sunxi: Add options for the SPL NAND configuration

The SPL image needs to be built with a different ECC configuration than the
U-Boot binary.

Add Kconfig options with defaults to provide a value that should work for
anyone, but is still configurable if needs be.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Scott Wood <oss@buserror.net>
Reviewed-by: Jagan Teki <jagan@openedev.com>