dt-bindings: mtd: fsl-upm-nand: Deprecate chip-delay and fsl, upm-wait-flags

Those properties are no longer parsed by the driver which is being passed
those information by the core now. Let's deprecate them.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200603134922.1352340-11-boris.brezillon@collabora.com