drm/i915: Only check for valid PP_{ON, OFF}_DELAYS on pre ILK hardware

ILK+ have this register on the PCH. This check was triggering unclaimed
writes.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_bios.c

@@ -762,7 +762,8 @@ void intel_setup_bios(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	 /* Set the Panel Power On/Off timings if uninitialized. */
-	if ((I915_READ(PP_ON_DELAYS) == 0) && (I915_READ(PP_OFF_DELAYS) == 0)) {
+	if (!HAS_PCH_SPLIT(dev) &&
+	    I915_READ(PP_ON_DELAYS) == 0 && I915_READ(PP_OFF_DELAYS) == 0) {
 		/* Set T2 to 40ms and T5 to 200ms */
 		I915_WRITE(PP_ON_DELAYS, 0x019007d0);