[S390] cpu topology support for s390.

Add s390 backend so we can give the scheduler some hints about the
cpu topology.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 8f894d3..5448aa8 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -67,9 +67,7 @@
 	CPU_STATE_CONFIGURED,
 };
 
-#ifdef CONFIG_HOTPLUG_CPU
-static DEFINE_MUTEX(smp_cpu_state_mutex);
-#endif
+DEFINE_MUTEX(smp_cpu_state_mutex);
 static int smp_cpu_state[NR_CPUS];
 
 static DEFINE_PER_CPU(struct cpu, cpu_devices);