sched: kfree(NULL) is valid

kfree(NULL) is valid.

pointed out by checkpatch.pl.

the fix shrinks the code a bit:

   text    data     bss     dec     hex filename
  40024    3842     100   43966    abbe sched.o.before
  40002    3842     100   43944    aba8 sched.o.after
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -6784,16 +6784,13 @@ struct task_grp *sched_create_group(void)
 
 err:
 	for_each_possible_cpu(i) {
-		if (tg->cfs_rq && tg->cfs_rq[i])
+		if (tg->cfs_rq)
 			kfree(tg->cfs_rq[i]);
-		if (tg->se && tg->se[i])
+		if (tg->se)
 			kfree(tg->se[i]);
 	}
-	if (tg->cfs_rq)
 	kfree(tg->cfs_rq);
-	if (tg->se)
 	kfree(tg->se);
-	if (tg)
 	kfree(tg);
 
 	return ERR_PTR(-ENOMEM);