drm/nouveau/disp/dp: create subclass for dp outputs

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/nv84.c b/drivers/gpu/drm/nouveau/core/engine/disp/nv84.c
index 98c5b19..436f0a5 100644
--- a/drivers/gpu/drm/nouveau/core/engine/disp/nv84.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/nv84.c
@@ -277,6 +277,7 @@
 		.init = _nouveau_disp_init,
 		.fini = _nouveau_disp_fini,
 	},
+	.base.outp =  nv50_disp_outp_sclass,
 	.mthd.core = &nv84_disp_mast_mthd_chan,
 	.mthd.base = &nv84_disp_sync_mthd_chan,
 	.mthd.ovly = &nv84_disp_ovly_mthd_chan,