x86, tsc: Fix a preemption leak in restore_sched_clock_state()

A real life genuine preemption leak..

Reported-and-tested-by: Jeff Chua <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Acked-by: Suresh Siddha <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index d632934..26a863a 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -655,7 +655,7 @@
 
 	local_irq_save(flags);
 
-	get_cpu_var(cyc2ns_offset) = 0;
+	__get_cpu_var(cyc2ns_offset) = 0;
 	offset = cyc2ns_suspend - sched_clock();
 
 	for_each_possible_cpu(cpu)