drm/i915: restore the early forcewake cleanup

Some BIOS just leak the forcewak bits, which we clean up.
Unfortunately this has been broken in

commit 521198a2e7095c8c7daa8d7d3a76a110c346be6f
Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date:   Fri Aug 23 16:52:30 2013 +0300

    drm/i915: sanitize forcewake registers on reset

To make this work both for resets and for BIOS takeover just add the
forcewake clearing call back to intel_uncore_early_sanitize.

We need to clear the forcewake in early sanitize so that the forcewak
dance in intel_uncore_init (to figure out whether we have mt or legacy
forcewake on ivb) works. That cleanup fits in nicely with the general
topic of early_sanitize to prepare for the very first mmio ops.

Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reported-by: Jörg Otte <jrg.otte@gmail.com>
Cc: Jörg Otte <jrg.otte@gmail.com>
References: https://lkml.org/lkml/2013/11/16/40
Cc: stable@vger.kernel.org (for 3.12 only)
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_uncore.c

@@ -217,6 +217,19 @@ static void gen6_force_wake_work(struct work_struct *work)
 	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
 }
 
+static void intel_uncore_forcewake_reset(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (IS_VALLEYVIEW(dev)) {
+		vlv_force_wake_reset(dev_priv);
+	} else if (INTEL_INFO(dev)->gen >= 6) {
+		__gen6_gt_force_wake_reset(dev_priv);
+		if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev))
+			__gen6_gt_force_wake_mt_reset(dev_priv);
+	}
+}
+
 void intel_uncore_early_sanitize(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -234,19 +247,8 @@ void intel_uncore_early_sanitize(struct drm_device *dev)
 		dev_priv->ellc_size = 128;
 		DRM_INFO("Found %zuMB of eLLC\n", dev_priv->ellc_size);
 	}
-}
 
-static void intel_uncore_forcewake_reset(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (IS_VALLEYVIEW(dev)) {
-		vlv_force_wake_reset(dev_priv);
-	} else if (INTEL_INFO(dev)->gen >= 6) {
-		__gen6_gt_force_wake_reset(dev_priv);
-		if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev))
-			__gen6_gt_force_wake_mt_reset(dev_priv);
-	}
+	intel_uncore_forcewake_reset(dev);
 }
 
 void intel_uncore_sanitize(struct drm_device *dev)