powerpc: Convert old cpumask API into new one

Adapt new API.

Almost change is trivial. Most important change is the below line
because we plan to change task->cpus_allowed implementation.

-       ctx->cpus_allowed = current->cpus_allowed;

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index ae6c27d..46f13a3 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -281,7 +281,7 @@
 	}
 
 	for_each_cpu(cpu, tmp) {
-		BUG_ON(cpumask_test_cpu(cpu, cpu_present_mask));
+		BUG_ON(cpu_present(cpu));
 		set_cpu_present(cpu, true);
 		set_hard_smp_processor_id(cpu, *intserv++);
 	}