cpuidle: mvebu: Fix the CPU PM notifier usage

commit 43b68879 upstream.

As stated in kernel/cpu_pm.c, "Platform is responsible for ensuring
that cpu_pm_enter is not called twice on the same CPU before
cpu_pm_exit is called.". In the current code in case of failure when
calling mvebu_v7_cpu_suspend, the function cpu_pm_exit() is never
called whereas cpu_pm_enter() was called just before.

This patch moves the cpu_pm_exit() in order to balance the
cpu_pm_enter() calls.
Reported-by: Fulvio Benini <fbf@libero.it>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[ luis: backported to 3.16:
  - file rename: cpuidle-mvebu-v7.c -> cpuidle-armada-370-xp.c
  - adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/cpuidle/cpuidle-armada-370-xp.c

@@ -38,11 +38,11 @@ static int armada_370_xp_enter_idle(struct cpuidle_device *dev,
 		deepidle = true;
 
 	ret = armada_370_xp_cpu_suspend(deepidle);
+	cpu_pm_exit();
+
 	if (ret)
 		return ret;
 
-	cpu_pm_exit();
-
 	return index;
 }