x86/acpi: process softirqs while printing CPU ACPI data

Or else the watchdog triggers on boxes with a huge number of CPUs

Reported-by: Simon Crowe <simon.crowe@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/acpi/cpu_idle.c

@@ -352,7 +352,10 @@ static void dump_cx(unsigned char key)
     printk("'%c' pressed -> printing ACPI Cx structures\n", key);
     for_each_online_cpu ( cpu )
         if (processor_powers[cpu])
+        {
             print_acpi_power(cpu, processor_powers[cpu]);
+            process_pending_softirqs();
+        }
 }
 
 static int __init cpu_idle_key_init(void)