drm/xe: make kobject type struct as constant

Since commit ee6d3dd4 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.

Take advantage of this to constify the structure definition to prevent
modification at runtime.
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_gt_sysfs.c

@@ -17,7 +17,7 @@ static void xe_gt_sysfs_kobj_release(struct kobject *kobj)
 	kfree(kobj);
 }
 
-static struct kobj_type xe_gt_sysfs_kobj_type = {
+static const struct kobj_type xe_gt_sysfs_kobj_type = {
 	.release = xe_gt_sysfs_kobj_release,
 	.sysfs_ops = &kobj_sysfs_ops,
 };