dt-bindings: nand: meson: make ECC properties dependent

dt-bindings: nand: meson: make ECC properties dependent

ECC properties 'nand-ecc-strength' and 'nand-ecc-step-size' depends on
each other, so they must be both either set or not set. In first case
ECC core will try to use these values if possible (by checking ECC caps
provided by driver), in second case ECC core will select most optimal
values for both properties.

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230717053402.1203724-2-AVKrasnov@sberdevices.ru