drm/i915: don't ironlake_init_pch_refclk() on LPT

This function is used to set the PCH_DREF_CONTROL register, which does
not exist on LPT anymore.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -504,7 +504,7 @@ static int i915_drm_thaw(struct drm_device *dev)
 
 	/* KMS EnterVT equivalent */
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-		if (HAS_PCH_SPLIT(dev))
+		if (HAS_PCH_IBX(dev) || HAS_PCH_CPT(dev))
 			ironlake_init_pch_refclk(dev);
 
 		mutex_lock(&dev->struct_mutex);