mtd: rawnand: davinci: Stop using nand_chip.legacy.IO_ADDR_{R, W}

We can use info->current_cs directly instead of doing this weird
IO_ADDR_{R,W} re-assignment dance.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200513172248.141402-2-boris.brezillon@collabora.com