drm/i915: Rename i915_opregion.c to intel_opregion.c

It's part of the generic Intel driver infrastructure so rename it in
prepreparation for using it for VBT.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 59457e8..3afd6e5 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -347,7 +347,7 @@
 
 
 	if (de_iir & DE_GSE)
-		ironlake_opregion_gse_intr(dev);
+		intel_opregion_gse_intr(dev);
 
 	if (de_iir & DE_PLANEA_FLIP_DONE) {
 		intel_prepare_page_flip(dev, 0);
@@ -1065,7 +1065,7 @@
 		if ((pipea_stats & PIPE_LEGACY_BLC_EVENT_STATUS) ||
 		    (pipeb_stats & PIPE_LEGACY_BLC_EVENT_STATUS) ||
 		    (iir & I915_ASLE_INTERRUPT))
-			opregion_asle_intr(dev);
+			intel_opregion_asle_intr(dev);
 
 		/* With MSI, interrupts are only generated when iir
 		 * transitions from zero to nonzero.  If another bit got
@@ -1252,7 +1252,7 @@
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	if (!HAS_PCH_SPLIT(dev))
-		opregion_enable_asle(dev);
+		intel_opregion_enable_asle(dev);
 	dev_priv->irq_enabled = 1;
 }
 
@@ -1570,7 +1570,7 @@
 		I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
 	}
 
-	opregion_enable_asle(dev);
+	intel_opregion_enable_asle(dev);
 
 	return 0;
 }