drm/nvc0: enable acceleration on 0xc8 by default

Worked well enough for glxgears and gnome-shell at least, no reason to
have this off anymore.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_state.c

@@ -1103,7 +1103,6 @@ int nouveau_load(struct drm_device *dev, unsigned long flags)
 	if (nouveau_noaccel == -1) {
 		switch (dev_priv->chipset) {
 		case 0xc1: /* known broken */
-		case 0xc8: /* never tested */
 			NV_INFO(dev, "acceleration disabled by default, pass "
 				     "noaccel=0 to force enable\n");
 			dev_priv->noaccel = true;