kexec jump: remove duplication of kexec_restart_prepare()

Call kernel_restart_prepare() in kernel_kexec() instead of duplicating the
code.

Signed-off-by: Huang Ying <[e-mail]>
Acked-by: Pavel Machek <[e-mail]>
Acked-by: Vivek Goyal <[e-mail]>
Cc: Pavel Machek <[e-mail]>
Cc: "Rafael J. Wysocki" <[e-mail]>
Cc: "Eric W. Biederman" <[e-mail]>
Cc: Vivek Goyal <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/reboot.h

···
  * Architecture independent implemenations of sys_reboot commands.
  */
 
+extern void kernel_restart_prepare(char *cmd);
 extern void kernel_restart(char *cmd);
 extern void kernel_halt(void);
 extern void kernel_power_off(void);

kernel/kexec.c

···
 	} else
 #endif
 	{
-		blocking_notifier_call_chain(&reboot_notifier_list,
-					     SYS_RESTART, NULL);
-		system_state = SYSTEM_RESTART;
-		device_shutdown();
-		sysdev_shutdown();
+		kernel_restart_prepare(NULL);
 		printk(KERN_EMERG "Starting new kernel\n");
 		machine_shutdown();
 	}

kernel/sys.c

···
 }
 EXPORT_SYMBOL_GPL(emergency_restart);
 
-static void kernel_restart_prepare(char *cmd)
+void kernel_restart_prepare(char *cmd)
 {
 	blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 	system_state = SYSTEM_RESTART;