clockevents/source: Use u64 to make 32bit happy

unsigned long is not 64bit on 32bit machine.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 22a9da9..c027d4f 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -197,7 +197,7 @@
 static void clockevents_config(struct clock_event_device *dev,
 			       u32 freq)
 {
-	unsigned long sec;
+	u64 sec;
 
 	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
 		return;