sched, nohz: Fix the idle cpu check in nohz_idle_balance

cpu bit in the nohz.idle_cpu_mask are reset in the first busy tick after
exiting idle. So during nohz_idle_balance(), intention is to double
check if the cpu that is part of the idle_cpu_mask is indeed idle before
going ahead in performing idle balance for that cpu.

Fix the cpu typo in the idle_cpu() check during nohz_idle_balance().

Reported-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1323199177.1984.12.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched/fair.c

@@ -5020,7 +5020,7 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle)
 		goto end;
 
 	for_each_cpu(balance_cpu, nohz.idle_cpus_mask) {
-		if (balance_cpu == this_cpu || !idle_cpu(this_cpu))
+		if (balance_cpu == this_cpu || !idle_cpu(balance_cpu))
 			continue;
 
 		/*