sched debug: remove NULL checking in print_cfs/rt_rq()

Impact: cleanup

cfs->tg is initialized in init_tg_cfs_entry() with tg != NULL, and
will never be invalidated to NULL. And the underlying cgroup of a
valid task_group is always valid.

Same for rt->tg.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/sched_debug.c

@@ -121,14 +121,9 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 
 #if defined(CONFIG_CGROUP_SCHED) && defined(CONFIG_FAIR_GROUP_SCHED)
 	char path[128] = "";
-	struct cgroup *cgroup = NULL;
 	struct task_group *tg = cfs_rq->tg;
 
-	if (tg)
-		cgroup = tg->css.cgroup;
-
-	if (cgroup)
-		cgroup_path(cgroup, path, sizeof(path));
+	cgroup_path(tg->css.cgroup, path, sizeof(path));
 
 	SEQ_printf(m, "\ncfs_rq[%d]:%s\n", cpu, path);
 #else
@@ -193,14 +188,9 @@ void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
 {
 #if defined(CONFIG_CGROUP_SCHED) && defined(CONFIG_RT_GROUP_SCHED)
 	char path[128] = "";
-	struct cgroup *cgroup = NULL;
 	struct task_group *tg = rt_rq->tg;
 
-	if (tg)
-		cgroup = tg->css.cgroup;
-
-	if (cgroup)
-		cgroup_path(cgroup, path, sizeof(path));
+	cgroup_path(tg->css.cgroup, path, sizeof(path));
 
 	SEQ_printf(m, "\nrt_rq[%d]:%s\n", cpu, path);
 #else