Revert "dma-buf: Report signaled links inside dma-fence-chain"

This reverts commit 5de376bb434f80a13138f0ebedc8351ab73d8b0d.

This change breaks synchronization of a timeline.
dma_fence_chain_find_seqno() might be a bit of a confusing name but
this function is not trying to find a particular seqno, is supposed to
give a fence to wait on for a particular point in the timeline.

In a timeline, a particular value is reached when all the points up to
and including that value have signaled.

Signed-off-by: Lionel Landwerlin <[e-mail]>
Reviewed-by: Christian König <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/372958/
Signed-off-by: Christian König <[e-mail]>

drivers/dma-buf/dma-fence-chain.c

···
 		return -EINVAL;
 
 	dma_fence_chain_for_each(*pfence, &chain->base) {
-		if ((*pfence)->seqno < seqno) { /* already signaled */
-			dma_fence_put(*pfence);
-			*pfence = NULL;
-			break;
-		}
-
 		if ((*pfence)->context != chain->base.context ||
 		    to_dma_fence_chain(*pfence)->prev_seqno < seqno)
 			break;
···
  * @chain: the chain node to initialize
  * @prev: the previous fence
  * @fence: the current fence
- * @seqno: the sequence number (syncpt) of the fence within the chain
  *
  * Initialize a new chain node and either start a new chain or add the node to
  * the existing chain of the previous fence.