mtd: nand: sunxi: Pass the device to the init function

This more closely matches the U-Boot driver to the Linux version.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Michael Trimarchi <micahel@amarulasolutions.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>