iio: magnetometer: ak8974: Drop dependency on OF

Nothing in this driver depends on OF firmware so drop the dependency
to remove the false impression such a dependency exists.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220413184502.20998-1-andriy.shevchenko@linux.intel.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/magnetometer/Kconfig

@@ -9,7 +9,6 @@ menu "Magnetometer sensors"
 config AK8974
 	tristate "Asahi Kasei AK8974 3-Axis Magnetometer"
 	depends on I2C
-	depends on OF
 	select REGMAP_I2C
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER