drm/nouveau: increase reservation sequence every retry

This is temporary until the fence framework can be used. With the
lru/reservation atomicity removal it is possible to see your old
sequence number and the buffer being reserved, leading to erroneously
reporting -EDEADLK.

Workaround it by bumping the sequence number every retry.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 8bf695c..9fcfcb2 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -321,8 +321,8 @@
 	int trycnt = 0;
 	int ret, i;
 
-	sequence = atomic_add_return(1, &drm->ttm.validate_sequence);
 retry:
+	sequence = atomic_add_return(1, &drm->ttm.validate_sequence);
 	if (++trycnt > 100000) {
 		NV_ERROR(drm, "%s failed and gave up.\n", __func__);
 		return -EINVAL;