PM / Domains: Move struct pm_domain_data to pm_domain.h

The definition of the struct pm_domain_data better belongs in the
header for the PM domains, let's move it there.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 383fd68..45e3e78 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -538,11 +538,7 @@
 };
 
 struct wakeup_source;
-
-struct pm_domain_data {
-	struct list_head list_node;
-	struct device *dev;
-};
+struct pm_domain_data;
 
 struct pm_subsys_data {
 	spinlock_t lock;