drm/i915: move pc8.irqs_disabled to pm.irqs_disabled

When other platforms add runtime PM support they will also need to
disable interrupts, so move the variable to the runtime PM struct.

Also notice that the longer-term goal is to completely kill the
regsave struct, and I even have patches for that.

v2: - Rebase.
v3: - Rebase.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@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 ddd0368..fcca82c 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6158,7 +6158,8 @@
 	mutex_init(&dev_priv->rps.hw_lock);
 
 	mutex_init(&dev_priv->pc8.lock);
-	dev_priv->pc8.irqs_disabled = false;
 	INIT_DELAYED_WORK(&dev_priv->rps.delayed_resume_work,
 			  intel_gen6_powersave_work);
+
+	dev_priv->pm.irqs_disabled = false;
 }