sched/topology: Add __init for init_defrootdomain

init_defrootdomain is only used in initialization
Signed-off-by: Bing Huang <huangbing@kylinos.cn>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lkml.kernel.org/r/20221118034208.267330-1-huangbing775@126.com

kernel/sched/topology.c

@@ -578,7 +578,7 @@ static int init_rootdomain(struct root_domain *rd)
  */
 struct root_domain def_root_domain;
 
-void init_defrootdomain(void)
+void __init init_defrootdomain(void)
 {
 	init_rootdomain(&def_root_domain);