drm/nouveau: remove unnecessary null pointer check from nouveau_fence_new

the variable chan is dereferenced in line 190, so it is no reason to check
null again in line 198.

Signed-off-by: Cong Ding <dinggnu@gmail.com>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_fence.c

@@ -195,11 +195,9 @@ nouveau_fence_new(struct nouveau_channel *chan, struct nouveau_fence **pfence)
 		return -ENOMEM;
 	kref_init(&fence->kref);
 
-	if (chan) {
-		ret = nouveau_fence_emit(fence, chan);
-		if (ret)
-			nouveau_fence_unref(&fence);
-	}
+	ret = nouveau_fence_emit(fence, chan);
+	if (ret)
+		nouveau_fence_unref(&fence);
 
 	*pfence = fence;
 	return ret;