locking, percpu_counter: Annotate ::lock as raw

The percpu_counter::lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 5edc901..b9df9ed 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -16,7 +16,7 @@
 #ifdef CONFIG_SMP
 
 struct percpu_counter {
-	spinlock_t lock;
+	raw_spinlock_t lock;
 	s64 count;
 #ifdef CONFIG_HOTPLUG_CPU
 	struct list_head list;	/* All percpu_counters are on a list */