tick: Fix the spurious broadcast timer ticks after resume

During resume, tick_resume_broadcast() programs the broadcast timer in
oneshot mode unconditionally. On the platforms where broadcast timer
is not really required, this will generate spurious broadcast timer
ticks upon resume. For example, on the always running apic timer
platforms with HPET, I see spurious hpet tick once every ~5minutes
(which is the 32-bit hpet counter wraparound time).

Similar to boot time, during resume make the oneshot mode setting of
the broadcast clock event device conditional on the state of active
broadcast users.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: svenjoac@gmx.de
Cc: torvalds@linux-foundation.org
Cc: rjw@sisk.pl
Link: http://lkml.kernel.org/r/1334802459.28674.209.camel@sbsiddha-desk.sc.intel.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/time/tick-broadcast.c

@@ -346,7 +346,8 @@ int tick_resume_broadcast(void)
 						     tick_get_broadcast_mask());
 			break;
 		case TICKDEV_MODE_ONESHOT:
-			broadcast = tick_resume_broadcast_oneshot(bc);
+			if (!cpumask_empty(tick_get_broadcast_mask()))
+				broadcast = tick_resume_broadcast_oneshot(bc);
 			break;
 		}
 	}