perf: perf_mux_hrtimer_cancel() can be static

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: kbuild-all@01.org
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150422200000.GA122603@lkp-sb04Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/events/core.c

@@ -773,7 +773,7 @@ static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
 }
 
 /* CPU is going down */
-void perf_mux_hrtimer_cancel(int cpu)
+static void perf_mux_hrtimer_cancel(int cpu)
 {
 	struct perf_cpu_context *cpuctx;
 	struct pmu *pmu;