drm/i915: Kill WA 0528

First of all I believe this WA as written here was wrong.

Because it is listed on BSpec only for SKL and BXT, exactly
the only 2 platforms skipped here.

But also it is written there that we don't need this WA
anymore:
"This workaround is no longer needed since NV12 support is
dropped for the affected projects in #0870."

SO, let's kill it.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Vidya Srinivas <vidya.srinivas@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181031162845.12419-1-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -455,18 +455,6 @@ static const struct intel_limit intel_limits_bxt = {
 	.p2 = { .p2_slow = 1, .p2_fast = 20 },
 };
 
-static void
-skl_wa_528(struct drm_i915_private *dev_priv, int pipe, bool enable)
-{
-	if (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv))
-		return;
-
-	if (enable)
-		I915_WRITE(CHICKEN_PIPESL_1(pipe), HSW_FBCQ_DIS);
-	else
-		I915_WRITE(CHICKEN_PIPESL_1(pipe), 0);
-}
-
 static void
 skl_wa_clkgate(struct drm_i915_private *dev_priv, int pipe, bool enable)
 {
@@ -5286,7 +5274,6 @@ static void intel_post_plane_update(struct intel_crtc_state *old_crtc_state)
 	if (needs_nv12_wa(dev_priv, old_crtc_state) &&
 	    !needs_nv12_wa(dev_priv, pipe_config)) {
 		skl_wa_clkgate(dev_priv, crtc->pipe, false);
-		skl_wa_528(dev_priv, crtc->pipe, false);
 	}
 }
 
@@ -5326,7 +5313,6 @@ static void intel_pre_plane_update(struct intel_crtc_state *old_crtc_state,
 	if (!needs_nv12_wa(dev_priv, old_crtc_state) &&
 	    needs_nv12_wa(dev_priv, pipe_config)) {
 		skl_wa_clkgate(dev_priv, crtc->pipe, true);
-		skl_wa_528(dev_priv, crtc->pipe, true);
 	}
 
 	/*