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/staging/iio/ring_sw.c b/drivers/staging/iio/ring_sw.c
index f61c8fd..3a45f9a 100644
--- a/drivers/staging/iio/ring_sw.c
+++ b/drivers/staging/iio/ring_sw.c
@@ -65,7 +65,7 @@
 /* Lock always held if their is a chance this may be called */
 /* Only one of these per ring may run concurrently - enforced by drivers */
 static int iio_store_to_sw_ring(struct iio_sw_ring_buffer *ring,
-				unsigned char *data, s64 timestamp)
+				unsigned char *data)
 {
 	int ret = 0;
 	unsigned char *temp_ptr, *change_test_ptr;
@@ -256,11 +256,10 @@
 }
 
 static int iio_store_to_sw_rb(struct iio_buffer *r,
-			      u8 *data,
-			      s64 timestamp)
+			      u8 *data)
 {
 	struct iio_sw_ring_buffer *ring = iio_to_sw_ring(r);
-	return iio_store_to_sw_ring(ring, data, timestamp);
+	return iio_store_to_sw_ring(ring, data);
 }
 
 static int iio_request_update_sw_rb(struct iio_buffer *r)