[S390] kexec: Disable ftrace during kexec

Disable ftrace during kexec. Same as on x86/powerpc.
ac4414e "powerpc/kdump: Disable ftrace during kexec".
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/machine_kexec.c

@@ -12,6 +12,7 @@
 #include <linux/kexec.h>
 #include <linux/delay.h>
 #include <linux/reboot.h>
+#include <linux/ftrace.h>
 #include <asm/cio.h>
 #include <asm/setup.h>
 #include <asm/pgtable.h>
@@ -71,6 +72,7 @@ static void __machine_kexec(void *data)
 
 void machine_kexec(struct kimage *image)
 {
+	tracer_disable();
 	smp_send_stop();
 	smp_switch_to_ipl_cpu(__machine_kexec, image);
 }