sched/fair: Remove stale tg_unthrottle_up() comments

After commit:

  82958366cfea ("sched: Replace update_shares weight distribution with per-entity computation")

tg_unthrottle_up() did not update the weight.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/lkml/1523423816-18322-1-git-send-email-lirongqing@baidu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/fair.c

@@ -4732,7 +4732,6 @@ static inline int throttled_lb_pair(struct task_group *tg,
 	       throttled_hierarchy(dest_cfs_rq);
 }
 
-/* updated child weight may affect parent so we have to do this bottom up */
 static int tg_unthrottle_up(struct task_group *tg, void *data)
 {
 	struct rq *rq = data;