PM / Domain: Add struct device to genpd

The power-domain core would be using the OPP core going forward and the
OPP core has the basic requirement of a device structure for its working.

Add a struct device to the genpd structure. This doesn't register the
device with device core as the "dev" pointer is mostly used by the OPP
core as a cookie for now and registering the device is not mandatory.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/base/power/domain.c

@@ -1696,6 +1696,9 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 			return ret;
 	}
 
+	device_initialize(&genpd->dev);
+	dev_set_name(&genpd->dev, "%s", genpd->name);
+
 	mutex_lock(&gpd_list_lock);
 	list_add(&genpd->gpd_list_node, &gpd_list);
 	mutex_unlock(&gpd_list_lock);