cpuidle: merge two if() statements for checking error cases

Two checks cpuidle_idle_call() cause the same error code to be
returned if they fail, so merge them for clarity.

[rjw: Changelog]
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpuidle/cpuidle.c

@@ -119,10 +119,7 @@ int cpuidle_idle_call(void)
 	struct cpuidle_driver *drv;
 	int next_state, entered_state;
 
-	if (off)
-		return -ENODEV;
-
-	if (!initialized)
+	if (off || !initialized)
 		return -ENODEV;
 
 	/* check if the device is ready */