ieee802154: at86rf230: Replace of_gpio.h by proper one

of_gpio.h is deprecated and subject to remove.
The driver doesn't use it directly, replace it
with what is really being used.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Message-ID: <20240304174218.1198411-1-andriy.shevchenko@linux.intel.com>
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>