drm/i915: Register ACPI video even when not modesetting

The ACPI video driver defers registration to the i915 driver if the
system supports opregion-mediated backlight control. This registration
was only being performed in the KMS case. Ensure it's done even if we
don't have modesetting enabled.

Signed-off-by: Matthew Garrett <[e-mail]>
Signed-off-by: Eric Anholt <[e-mail]>

drivers/gpu/drm/i915/i915_opregion.c

···
 	if (mboxes & MBOX_ACPI) {
 		DRM_DEBUG("Public ACPI methods supported\n");
 		opregion->acpi = base + OPREGION_ACPI_OFFSET;
-		if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		if (drm_core_check_feature(dev, DRIVER_MODESET))
 			intel_didl_outputs(dev);
-			if (!resume)
-				acpi_video_register();
-		}
 	} else {
 		DRM_DEBUG("Public ACPI methods not supported\n");
 		err = -ENOTSUPP;
···
 		DRM_DEBUG("ASLE supported\n");
 		opregion->asle = base + OPREGION_ASLE_OFFSET;
 	}
+
+	if (!resume)
+		acpi_video_register();
+
 
 	/* Notify BIOS we are ready to handle ACPI video ext notifs.
 	 * Right now, all the events are handled by the ACPI video module.