x86, apbt: Setup affinity for apb timers acting as per-cpu timer

Commit a5ef2e70 "x86: Sanitize apb timer interrupt handling" forgot
the affinity setup when cleaning up the code, this patch just
adds the forgotten part

Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Jacob Pan <jacob.jun.pan@intel.com>
Cc: Alan Cox <alan@linux.intel.com>
LKML-Reference: <1291348298-21263-2-git-send-email-feng.tang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/apb_timer.c

@@ -315,6 +315,7 @@ static void apbt_setup_irq(struct apbt_dev *adev)
 
 	if (system_state == SYSTEM_BOOTING) {
 		irq_modify_status(adev->irq, 0, IRQ_MOVE_PCNTXT);
+		irq_set_affinity(adev->irq, cpumask_of(adev->cpu));
 		/* APB timer irqs are set up as mp_irqs, timer is edge type */
 		__set_irq_handler(adev->irq, handle_edge_irq, 0, "edge");
 		if (request_irq(adev->irq, apbt_interrupt_handler,