iio: Drop timestamp parameter from buffer store_to callback

Drop timestamp parameter from buffer store_to callback and subsequently from
iio_push_to_buffer. The timestamp parameter is unused and it seems likely that
it will stay unused in the future, so it should be safe to remove it.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
index 63da424..5bc5c860 100644
--- a/drivers/iio/kfifo_buf.c
+++ b/drivers/iio/kfifo_buf.c
@@ -95,8 +95,7 @@
 }
 
 static int iio_store_to_kfifo(struct iio_buffer *r,
-			      u8 *data,
-			      s64 timestamp)
+			      u8 *data)
 {
 	int ret;
 	struct iio_kfifo *kf = iio_to_kfifo(r);