[S390] ftrace: add function graph tracer support

Function graph tracer support for s390.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/s390_ext.c b/arch/s390/kernel/s390_ext.c
index 6b0686d..0de305b 100644
--- a/arch/s390/kernel/s390_ext.c
+++ b/arch/s390/kernel/s390_ext.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
+#include <linux/ftrace.h>
 #include <linux/errno.h>
 #include <linux/kernel_stat.h>
 #include <linux/interrupt.h>
@@ -112,7 +113,7 @@
 	return 0;
 }
 
-void do_extint(struct pt_regs *regs, unsigned short code)
+void __irq_entry do_extint(struct pt_regs *regs, unsigned short code)
 {
         ext_int_info_t *p;
         int index;