drm/nvd0/disp: push the update button in mode_set_base()

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nvd0_display.c b/drivers/gpu/drm/nouveau/nvd0_display.c
index 376acc1..4fadea4 100644
--- a/drivers/gpu/drm/nouveau/nvd0_display.c
+++ b/drivers/gpu/drm/nouveau/nvd0_display.c
@@ -192,6 +192,10 @@
 		evo_data(push, nvfb->r_pitch);
 		evo_data(push, nvfb->r_format);
 		evo_data(push, nvfb->r_dma);
+		if (update) {
+			evo_mthd(push, 0x0080, 1);
+			evo_data(push, 0x00000000);
+		}
 		evo_kick(push, fb->dev, 0);
 	}