mtd: rawnand: meson: use NAND core API to check status

NAND core API already has functions to send NAND_CMD_STATUS and leave
status checking mode by sending NAND_CMD_READ0, so use both of them
instead of direct access to the controller registers.

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230705104403.696680-3-AVKrasnov@sberdevices.ru