iio: buffer: document iio_push_to_buffers_with_ts_unaligned() may sleep

Add Context: documentation comment that
iio_push_to_buffers_with_ts_unaligned() may sleep because it calls
devm_krealloc().

Also document Return: value while here.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/industrialio-buffer.c

@@ -2401,6 +2401,9 @@ EXPORT_SYMBOL_GPL(iio_push_to_buffers);
  * not require space for the timestamp, or 8 byte alignment of data.
  * It does however require an allocation on first call and additional
  * copies on all calls, so should be avoided if possible.
+ *
+ * Context: May sleep.
+ * Return: 0 on success, negative error code on failure.
  */
 int iio_push_to_buffers_with_ts_unaligned(struct iio_dev *indio_dev,
 					  const void *data,