Driver core: remove use of rwsem

This lock is never used by the rest of the driver core, so the fact that
we are grabbing it here means it isn't correct...
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/power/shutdown.c

@@ -36,7 +36,6 @@ void device_shutdown(void)
 {
 	struct device * dev, *devn;
 
-	down_write(&devices_subsys.rwsem);
 	list_for_each_entry_safe_reverse(dev, devn, &devices_subsys.kset.list,
 				kobj.entry) {
 		if (dev->bus && dev->bus->shutdown) {
@@ -47,7 +46,6 @@ void device_shutdown(void)
 			dev->driver->shutdown(dev);
 		}
 	}
-	up_write(&devices_subsys.rwsem);
 
 	sysdev_shutdown();
 }