drm/nouveau/disp: introduce proper init/fini, separate from create/destroy

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nv04_display.c b/drivers/gpu/drm/nouveau/nv04_display.c
index 6bd8518..7047d37 100644
--- a/drivers/gpu/drm/nouveau/nv04_display.c
+++ b/drivers/gpu/drm/nouveau/nv04_display.c
@@ -243,6 +243,11 @@
 	return 0;
 }
 
+void
+nv04_display_fini(struct drm_device *dev)
+{
+}
+
 static void
 nv04_vblank_crtc0_isr(struct drm_device *dev)
 {