drm/i915: Drop some more CHV pre-production workarounds

Drop WaDisablePwrmtrEvent:chv as it's no longer needed.

Also remove the WaSetMaskForGfxBusyness:chv note, but we still
leave the GEN6_RP_MEDIA_IS_GFX bit enabled as that's still the
recommended setting.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Arun Siluvery <arun.siluvery@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -4789,14 +4789,10 @@ static void cherryview_enable_rps(struct drm_device *dev)
 
 	I915_WRITE(GEN6_RP_IDLE_HYSTERSIS, 10);
 
-	/* WaDisablePwrmtrEvent:chv (pre-production hw) */
-	I915_WRITE(0xA80C, I915_READ(0xA80C) & 0x00ffffff);
-	I915_WRITE(0xA810, I915_READ(0xA810) & 0xffffff00);
-
 	/* 5: Enable RPS */
 	I915_WRITE(GEN6_RP_CONTROL,
 		   GEN6_RP_MEDIA_HW_NORMAL_MODE |
-		   GEN6_RP_MEDIA_IS_GFX | /* WaSetMaskForGfxBusyness:chv (pre-production hw ?) */
+		   GEN6_RP_MEDIA_IS_GFX |
 		   GEN6_RP_ENABLE |
 		   GEN6_RP_UP_BUSY_AVG |
 		   GEN6_RP_DOWN_IDLE_AVG);