drm/i915: Nuke lvds downclock support

With the new DRRS code it kinda sticks out, and we never managed to
get this to work well enough without causing issues. Time to wave
goodbye.

I've decided to keep the logic for programming the reduced clocks
intact, but everything else is gone. If anyone ever wants to resurrect
this we need to redo it all anyway on top of the frontbuffer tracking.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index bf1702a..ea85547 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -1072,24 +1072,8 @@
 			drm_mode_debug_printmodeline(scan);
 
 			fixed_mode = drm_mode_duplicate(dev, scan);
-			if (fixed_mode) {
-				downclock_mode =
-					intel_find_panel_downclock(dev,
-					fixed_mode, connector);
-				if (downclock_mode != NULL &&
-					i915.lvds_downclock) {
-					/* We found the downclock for LVDS. */
-					dev_priv->lvds_downclock_avail = true;
-					dev_priv->lvds_downclock =
-						downclock_mode->clock;
-					DRM_DEBUG_KMS("LVDS downclock is found"
-					" in EDID. Normal clock %dKhz, "
-					"downclock %dKhz\n",
-					fixed_mode->clock,
-					dev_priv->lvds_downclock);
-				}
+			if (fixed_mode)
 				goto out;
-			}
 		}
 	}