nouveau: fixup scanout enable in nvc0_pm

Fixes screen being black after changing performance level.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: stable@vger.kernel.org [3.5+]
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvc0_pm.c

@@ -557,7 +557,7 @@ prog_mem(struct drm_device *dev, struct nvc0_pm_state *info)
 	nouveau_mem_exec(&exec, info->perflvl);
 
 	if (dev_priv->chipset < 0xd0)
-		nv_wr32(dev, 0x611200, 0x00003300);
+		nv_wr32(dev, 0x611200, 0x00003330);
 	else
 		nv_wr32(dev, 0x62c000, 0x03030300);
 }