iio:adc:ad7923: Add support for the ad7904/ad7914/ad7924

The ad7924 is software compatible with the ad7923. The ad7904 and ad7914 are the
8 and 10 bit version of the ad7924.

While we are at it also drop the "with temperature sensor" from the Kconfig
entry, since the chips do not have a temperature sensor.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Patrick Vasseur <patrick.vasseur@c-s.fr>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 9c45c0f..ab0767e6 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -31,13 +31,13 @@
 	  module will be called ad7298.
 
 config AD7923
-	tristate "Analog Devices AD7923 ADC driver"
+	tristate "Analog Devices AD7923 and similar ADCs driver"
 	depends on SPI
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 	help
-	  Say yes here to build support for Analog Devices AD7923
-	  4 Channel ADC with temperature sensor.
+	  Say yes here to build support for Analog Devices
+	  AD7904, AD7914, AD7923, AD7924 4 Channel ADCs.
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad7923.