mtd: rawnand: davinci: use generic device property helpers

There's no reason for this driver to be using OF-specific property
accessors. Switch to using generic device property interfaces and
replace the of.h include with property.h. This allows us to no longer
check the existence of the associated of_node.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20241007122350.75285-3-brgl@bgdev.pl