reservation: revert "wait only with non-zero timeout specified (v3)" v2

Reverts commit fb8b7d2b9d
	("reservation: wait only with non-zero timeout specified (v3)")

Otherwise signaling might never be activated on the fences. This can
result in infinite waiting with hardware which has unreliable interrupts.

v2: still return one when the timeout is zero and we don't have any fences.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com> (v1)
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
  [sumits: fix checkpatch warnings]
Link: http://patchwork.freedesktop.org/patch/msgid/1478553376-18575-4-git-send-email-alexander.deucher@amd.com

drivers/dma-buf/reservation.c

@@ -370,10 +370,7 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
 {
 	struct dma_fence *fence;
 	unsigned seq, shared_count, i = 0;
-	long ret = timeout;
-
-	if (!timeout)
-		return reservation_object_test_signaled_rcu(obj, wait_all);
+	long ret = timeout ? timeout : 1;
 
 retry:
 	fence = NULL;