timer: process softirq during dumping timer info

Dumping timer info may run for a long time on the huge machine with
a lot of physical cpus. To avoid triggering NMI watchdog, add
process_pending_softirqs() in the loop of dumping timer info.

Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/common/timer.c

@@ -530,6 +530,7 @@ static void dump_timerq(unsigned char key)
     {
         ts = &per_cpu(timers, i);
 
+        process_pending_softirqs();
         printk("CPU%02d:\n", i);
         spin_lock_irqsave(&ts->lock, flags);
         for ( j = 1; j <= GET_HEAP_SIZE(ts->heap); j++ )