PM / Runtime: Allow helpers to be called by early platform drivers

Runtime PM helper functions, like pm_runtime_get_sync(), cannot be
called by early platform device drivers, because the devices' power
management locks are not initialized at that time.  This is quite
inconvenient, so modify early_platform_add_devices() to initialize
the devices power management locks as appropriate and make sure that
they won't be initialized more than once if an early platform
device is going to be used as a regular one later.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index 8a0dcc7..0dbfdf4 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -2,17 +2,31 @@
 
 static inline void device_pm_init_common(struct device *dev)
 {
-	spin_lock_init(&dev->power.lock);
-	dev->power.power_state = PMSG_INVALID;
+	if (!dev->power.early_init) {
+		spin_lock_init(&dev->power.lock);
+		dev->power.power_state = PMSG_INVALID;
+		dev->power.early_init = true;
+	}
 }
 
 #ifdef CONFIG_PM_RUNTIME
 
+static inline void pm_runtime_early_init(struct device *dev)
+{
+	dev->power.disable_depth = 1;
+	device_pm_init_common(dev);
+}
+
 extern void pm_runtime_init(struct device *dev);
 extern void pm_runtime_remove(struct device *dev);
 
 #else /* !CONFIG_PM_RUNTIME */
 
+static inline void pm_runtime_early_init(struct device *dev)
+{
+	device_pm_init_common(dev);
+}
+
 static inline void pm_runtime_init(struct device *dev) {}
 static inline void pm_runtime_remove(struct device *dev) {}