PM / sleep: Make suspend-to-idle-specific code depend on CONFIG_SUSPEND

Since idle_should_freeze() is defined to always return 'false'
for CONFIG_SUSPEND unset, all of the code depending on it in
cpuidle_idle_call() is not necessary in that case.

Make that code depend on CONFIG_SUSPEND too to avoid building it
when it is not going to be used.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

drivers/cpuidle/cpuidle.c

@@ -92,6 +92,7 @@ static int find_deepest_state(struct cpuidle_driver *drv,
 	return ret;
 }
 
+#ifdef CONFIG_SUSPEND
 /**
  * cpuidle_find_deepest_state - Find the deepest available idle state.
  * @drv: cpuidle driver for the given CPU.
@@ -145,6 +146,7 @@ int cpuidle_enter_freeze(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 
 	return index;
 }
+#endif /* CONFIG_SUSPEND */
 
 /**
  * cpuidle_enter_state - enter the state and update stats