cpumask: convert struct clock_event_device to cpumask pointers.

Impact: change calling convention of existing clock_event APIs

struct clock_event_timer's cpumask field gets changed to take pointer,
as does the ->broadcast function.

Another single-patch change.  For safety, we BUG_ON() in
clockevents_register_device() if it's not set.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>

arch/arm/mach-ns9xxx/time-ns9360.c

@@ -173,7 +173,7 @@ static void __init ns9360_timer_init(void)
 	ns9360_clockevent_device.min_delta_ns =
 		clockevent_delta2ns(1, &ns9360_clockevent_device);
 
-	ns9360_clockevent_device.cpumask = cpumask_of_cpu(0);
+	ns9360_clockevent_device.cpumask = cpumask_of(0);
 	clockevents_register_device(&ns9360_clockevent_device);
 
 	setup_irq(IRQ_NS9360_TIMER0 + TIMER_CLOCKEVENT,