iio: humidity: am2315: set up buffer timestamps for non-zero values

commit 3c68858d 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>
Reviewed-By: Tiberiu Breana <tiberiu.a.breana@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/iio/humidity/am2315.c

@@ -244,7 +244,7 @@ static int am2315_probe(struct i2c_client *client,
 	indio_dev->channels = am2315_channels;
 	indio_dev->num_channels = ARRAY_SIZE(am2315_channels);
 
-	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
 					 am2315_trigger_handler, NULL);
 	if (ret < 0) {
 		dev_err(&client->dev, "iio triggered buffer setup failed\n");