iio: adc: sd_adc_modulator: Drop dependency on OF

Nothing in this driver depends on OF 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/20220530181706.3045-1-andriy.shevchenko@linux.intel.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/Kconfig

@@ -941,7 +941,6 @@ config SPEAR_ADC
 
 config SD_ADC_MODULATOR
 	tristate "Generic sigma delta modulator"
-	depends on OF
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 	help