iio:triggers:interrupt trigger - move out of staging.

This is now a very simple trigger indeed but useful in many common cases.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

drivers/iio/trigger/Kconfig

@@ -3,6 +3,15 @@
 #
 menu "Triggers - standalone"
 
+config IIO_INTERRUPT_TRIGGER
+	tristate "Generic interrupt trigger"
+	help
+	  Provides support for using an interrupt of any type as an IIO
+	  trigger.  This may be provided by a gpio driver for example.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called iio-trig-interrupt.
+
 config IIO_SYSFS_TRIGGER
 	tristate "SYSFS trigger"
 	depends on SYSFS