drm/nouveau: assign fence_chan->name correctly

Make nouveau_fence_chan refcounted, to make trace_fence_destroy
always return the correct name without a race condition.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
diff --git a/drivers/gpu/drm/nouveau/nv04_fence.c b/drivers/gpu/drm/nouveau/nv04_fence.c
index 4484131..f9859de 100644
--- a/drivers/gpu/drm/nouveau/nv04_fence.c
+++ b/drivers/gpu/drm/nouveau/nv04_fence.c
@@ -67,7 +67,7 @@
 	struct nv04_fence_chan *fctx = chan->fence;
 	nouveau_fence_context_del(&fctx->base);
 	chan->fence = NULL;
-	kfree(fctx);
+	nouveau_fence_context_free(&fctx->base);
 }
 
 static int