staging:iio:dummy Add event support + fake event generator

The event generator is not very pretty but does the job and
allows this driver to look a lot more like a normal driver
than it otherwise would.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/iio/iio_dummy_evgen.h b/drivers/staging/iio/iio_dummy_evgen.h
new file mode 100644
index 0000000..d8845e2
--- /dev/null
+++ b/drivers/staging/iio/iio_dummy_evgen.h
@@ -0,0 +1,2 @@
+int iio_dummy_evgen_get_irq(void);
+int iio_dummy_evgen_release_irq(int irq);