iio: light: Annotate Kconfig entry with module name information

This patch fixes the following checkpatch.pl warning:
WARNING: please write a paragraph that describes the config symbol fully
Signed-off-by: Roberta Dobrescu <roberta.dobrescu@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/Kconfig

@@ -95,6 +95,9 @@ config HID_SENSOR_ALS
 	  Say yes here to build support for the HID SENSOR
 	  Ambient light sensor.
 
+	  To compile this driver as a module, choose M here: the
+	  module will be called hid-sensor-als.
+
 config HID_SENSOR_PROX
 	depends on HID_SENSOR_HUB
 	select IIO_BUFFER