ARM: AT91: IIO: Add AT91 ADC driver.

Add the ADC driver for Atmel's AT91SAM9G20-EK, AT91SAM9M10G45-EK
and AT91SAM9X5 family boards.

It has support for both software and hardware triggers.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index bb1e35c..56eecef 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -48,6 +48,7 @@
 	This value controls the maximum number of consumers that a
 	given trigger may handle. Default is 2.
 
+source "drivers/iio/adc/Kconfig"
 source "drivers/iio/amplifiers/Kconfig"
 
 endif # IIO