iio:adc/dac:Kconfig: Update to drop OF dependencies.

We could probably drop a lot more of these, but for now this removes
unnecessary restrictions on stand alone ADC devices.

For these 3 drivers the false dependency seems to date all
the way back to their initial introduction.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

drivers/iio/adc/Kconfig

@@ -1146,7 +1146,7 @@ config TI_ADS7950
 
 config TI_ADS8344
 	tristate "Texas Instruments ADS8344"
-	depends on SPI && OF
+	depends on SPI
 	help
 	  If you say yes here you get support for Texas Instruments ADS8344
 	  ADC chips
@@ -1156,7 +1156,7 @@ config TI_ADS8344
 
 config TI_ADS8688
 	tristate "Texas Instruments ADS8688"
-	depends on SPI && OF
+	depends on SPI
 	help
 	  If you say yes here you get support for Texas Instruments ADS8684 and
 	  and ADS8688 ADC chips

drivers/iio/dac/Kconfig

@@ -340,7 +340,6 @@ config MAX517
 config MAX5821
 	tristate "Maxim MAX5821 DAC driver"
 	depends on I2C
-	depends on OF
 	help
 	  Say yes here to build support for Maxim MAX5821
 	  10 bits DAC.