cpumask: make Xen use the new operators.

Impact: cleanup

In particular, *map are deprecated, and you have to use the accessors
as *mask are const.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
To: Jeremy Fitzhardinge <jeremy@xensource.com>

drivers/xen/cpu_hotplug.c

@@ -10,15 +10,15 @@ static void enable_hotplug_cpu(int cpu)
 	if (!cpu_present(cpu))
 		arch_register_cpu(cpu);
 
-	cpu_set(cpu, cpu_present_map);
+	set_cpu_present(cpu, true);
 }
 
 static void disable_hotplug_cpu(int cpu)
 {
 	if (cpu_present(cpu))
 		arch_unregister_cpu(cpu);
 
-	cpu_clear(cpu, cpu_present_map);
+	set_cpu_present(cpu, false);
 }
 
 static void vcpu_hotplug(unsigned int cpu)