gpio: nomadik: replace of_find_*() by bus_find_device_by_of_node()

Avoid OF APIs in the GPIO subsystem. Here, replace
of_find_device_by_node() call by bus_find_device_by_of_node().

The new helper returns a struct device pointer. Store it in a new local
variable and use it down the road.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20240228-mbly-gpio-v2-15-3ba757474006@bootlin.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>