kexec jump: in sync with hibernation implementation

Add device_pm_lock() and device_pm_unlock() in kernel_kexec() in sync with
current hibernation implementation.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/kexec.c

@@ -1457,6 +1457,7 @@ int kernel_kexec(void)
 		error = disable_nonboot_cpus();
 		if (error)
 			goto Resume_devices;
+		device_pm_lock();
 		local_irq_disable();
 		/* At this point, device_suspend() has been called,
 		 * but *not* device_power_down(). We *must*
@@ -1485,6 +1486,7 @@ int kernel_kexec(void)
 		device_power_up(PMSG_RESTORE);
  Enable_irqs:
 		local_irq_enable();
+		device_pm_unlock();
 		enable_nonboot_cpus();
  Resume_devices:
 		device_resume(PMSG_RESTORE);