drm/i915/wm: warn about ilk_wm_sanitize() on display ver 9+

The sanitization should be limited to PCH split platforms up to display
version 8. Warn and bail out otherwise.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230215141910.433043-2-jani.nikula@intel.com

drivers/gpu/drm/i915/display/i9xx_wm.c

@@ -3437,6 +3437,9 @@ void ilk_wm_sanitize(struct drm_i915_private *dev_priv)
 	if (!dev_priv->display.funcs.wm->optimize_watermarks)
 		return;
 
+	if (drm_WARN_ON(&dev_priv->drm, DISPLAY_VER(dev_priv) >= 9))
+		return;
+
 	state = drm_atomic_state_alloc(&dev_priv->drm);
 	if (drm_WARN_ON(&dev_priv->drm, !state))
 		return;