drm/i915: Fix LVDS dither setting

Update bdb_lvds_options structure according to its defination in
2D driver. Then we can parse and set 'lvds_dither' bit correctly
on non-965 chips.

Signed-off-by: Li Peng <peng.li@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 0d211af..6619f26 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -265,7 +265,7 @@
 		pfit_control = 0;
 
 	if (!IS_I965G(dev)) {
-		if (dev_priv->panel_wants_dither)
+		if (dev_priv->panel_wants_dither || dev_priv->lvds_dither)
 			pfit_control |= PANEL_8TO6_DITHER_ENABLE;
 	}
 	else