PM / Runtime: Implement the pm_generic_runtime functions for CONFIG_PM

The pm_generic_runtime_suspend|resume functions were implemented within
CONFIG_PM_RUNTIME.

As we also may use runtime PM callbacks during system suspend, to put
devices into low power state, we need to move the implementation of
pm_generic_runtime_suspend|resume to CONFIG_PM.

This change gives a power domain provision to invoke a platform
driver's runtime PM callback from a power domain's system PM callback.
This were earlier prevented by the platform bus, since it uses the
pm_generic_runtime_suspend|resume functions as runtime PM callbacks.

Cc: Kevin Hilman <[e-mail]>
Cc: Alan Stern <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/base/power/generic_ops.c

···
 #include <linux/pm_runtime.h>
 #include <linux/export.h>
 
-#ifdef CONFIG_PM_RUNTIME
+#ifdef CONFIG_PM
 /**
  * pm_generic_runtime_suspend - Generic runtime suspend callback for subsystems.
  * @dev: Device to suspend.
···
 	return ret;
 }
 EXPORT_SYMBOL_GPL(pm_generic_runtime_resume);
-#endif /* CONFIG_PM_RUNTIME */
+#endif /* CONFIG_PM */
 
 #ifdef CONFIG_PM_SLEEP
 /**

include/linux/pm_runtime.h

···
 					    usage_count */
 #define RPM_AUTO		0x08	/* Use autosuspend_delay */
 
+#ifdef CONFIG_PM
+extern int pm_generic_runtime_suspend(struct device *dev);
+extern int pm_generic_runtime_resume(struct device *dev);
+#else
+static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
+static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
+#endif
+
 #ifdef CONFIG_PM_RUNTIME
 
 extern struct workqueue_struct *pm_wq;
···
 extern void __pm_runtime_disable(struct device *dev, bool check_resume);
 extern void pm_runtime_allow(struct device *dev);
 extern void pm_runtime_forbid(struct device *dev);
-extern int pm_generic_runtime_suspend(struct device *dev);
-extern int pm_generic_runtime_resume(struct device *dev);
 extern void pm_runtime_no_callbacks(struct device *dev);
 extern void pm_runtime_irq_safe(struct device *dev);
 extern void __pm_runtime_use_autosuspend(struct device *dev, bool use);
···
 static inline bool pm_runtime_status_suspended(struct device *dev) { return false; }
 static inline bool pm_runtime_enabled(struct device *dev) { return false; }
 
-static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
-static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
 static inline void pm_runtime_no_callbacks(struct device *dev) {}
 static inline void pm_runtime_irq_safe(struct device *dev) {}