drm/nouveau/disp: allow user direct access to channel control registers

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
index 82d6b4f..9e9fa58 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -69,8 +69,10 @@
 		int ret = nvif_object_init(disp, NULL, (oclass[0] << 16) | head,
 					   oclass[0], data, size,
 					  &chan->user);
-		if (oclass++, ret == 0)
+		if (oclass++, ret == 0) {
+			nvif_object_map(&chan->user);
 			return ret;
+		}
 	}
 	return -ENOSYS;
 }