Perf: Check perf activity on correct CPU

The CPU hotplug notifier is not always preempt safe.
So relying on smp_processor_id() is not correct.

Use the cpu id from the notifier as the target
CPU to check for perf activity before hotplug or power
collapse.

Change-Id: I1a96b236904a2c8ae2f82bbceab4ca8a195395d1
Signed-off-by: Ashwin Chaugule <ashwinc@codeaurora.org>
diff --git a/arch/arm/mach-msm/perf_debug.c b/arch/arm/mach-msm/perf_debug.c
index bbd0852..8994f28 100644
--- a/arch/arm/mach-msm/perf_debug.c
+++ b/arch/arm/mach-msm/perf_debug.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -26,6 +26,7 @@
 	"1  Perf: Restore counter after powercollapse for generic ARM PMU's\n"
 	"2  Perf: Toggle PMU IRQ when CPU's are hotplugged\n"
 	"3  Perf: Correct irq for CPU hotplug detection\n"
+	"4  Perf: Check perf activity on correct CPU\n"
 ;
 
 static ssize_t desc_read(struct file *fp, char __user *buf,