drm/i915/skl: Double RC6 WRL always on

WaRsDoubleRc6WrlWithCoarsePowerGating should
be enabled for all Skylakes. Make it so.

Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449505785-20812-2-git-send-email-mika.kuoppala@intel.com
(cherry picked from commit e7674b8c31717dd0c58b3a9493d43249722071eb)
Cc: stable@vger.kernel.org # v4.3+
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -4782,8 +4782,7 @@ static void gen9_enable_rc6(struct drm_device *dev)
 	/* 2b: Program RC6 thresholds.*/
 
 	/* WaRsDoubleRc6WrlWithCoarsePowerGating: Doubling WRL only when CPG is enabled */
-	if (IS_SKYLAKE(dev) && !((IS_SKL_GT3(dev) || IS_SKL_GT4(dev)) &&
-				 (INTEL_REVID(dev) <= SKL_REVID_E0)))
+	if (IS_SKYLAKE(dev))
 		I915_WRITE(GEN6_RC6_WAKE_RATE_LIMIT, 108 << 16);
 	else
 		I915_WRITE(GEN6_RC6_WAKE_RATE_LIMIT, 54 << 16);