[S390] Fix build errors (fallout from system.h disintegration)

Signed-off-by: Heiko Carstens <h.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index 8481ecf..4640508 100644
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -18,7 +18,7 @@
 #include <linux/notifier.h>
 #include <linux/init.h>
 #include <linux/export.h>
-#include <asm/system.h>
+#include <asm/ctl_reg.h>
 #include <asm/irq.h>
 #include <asm/cpu_mf.h>