drm/i915/dvo: Remove unused panel_wants_dither

intel_dvo.panel_wants_dither is only set but never used.
We can't do dithering on the gmch side anyway since the
dithering logic is part of the integrated LVDS port and
not available for other output types.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221118105525.27254-2-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_dvo.c

@@ -118,8 +118,6 @@ struct intel_dvo {
 	struct intel_dvo_device dev;
 
 	struct intel_connector *attached_connector;
-
-	bool panel_wants_dither;
 };
 
 static struct intel_dvo *enc_to_dvo(struct intel_encoder *encoder)
@@ -531,8 +529,6 @@ void intel_dvo_init(struct drm_i915_private *dev_priv)
 							   intel_encoder);
 
 			intel_panel_init(intel_connector);
-
-			intel_dvo->panel_wants_dither = true;
 		}
 
 		return;