drm/i915: use runtime irq suspend/resume in freeze/thaw

We don't need to uninstall the full handler, simply disabling interrupts
ought to be enough.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 8148d06..1cce0a5 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4880,7 +4880,7 @@
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	/* Interrupts should be disabled already to avoid re-arming. */
-	WARN_ON(dev->irq_enabled);
+	WARN_ON(dev->irq_enabled && !dev_priv->pm.irqs_disabled);
 
 	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
 
@@ -4892,7 +4892,7 @@
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	/* Interrupts should be disabled already to avoid re-arming. */
-	WARN_ON(dev->irq_enabled);
+	WARN_ON(dev->irq_enabled && !dev_priv->pm.irqs_disabled);
 
 	if (IS_IRONLAKE_M(dev)) {
 		ironlake_disable_drps(dev);