iio: proximity: as3935: set up buffer timestamps for non-zero values

commit f8adf645 upstream.

Use the iio_pollfunc_store_time parameter during triggered buffer
set-up to get valid timestamps.
Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/iio/proximity/as3935.c

@@ -389,7 +389,7 @@ static int as3935_probe(struct spi_device *spi)
 		return ret;
 	}
 
-	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
 		&as3935_trigger_handler, NULL);
 
 	if (ret) {