driver core: dd: remove deferred_devices variable

No need to save the debugfs dentry for the "devices_deferred" debugfs
file (gotta love the juxtaposition), if we need to remove it we can look
it up from debugfs itself.

Cc: "Rafael J. Wysocki" <[e-mail]>
Cc: [e-mail]
Reviewed-by: Rafael J. Wysocki <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/base/dd.c

···
 static LIST_HEAD(deferred_probe_pending_list);
 static LIST_HEAD(deferred_probe_active_list);
 static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
-static struct dentry *deferred_devices;
 static bool initcalls_done;
 
 /* Save the async probe drivers' name from kernel cmdline */
···
  */
 static int deferred_probe_initcall(void)
 {
-	deferred_devices = debugfs_create_file("devices_deferred", 0444, NULL,
-					       NULL, &deferred_devs_fops);
+	debugfs_create_file("devices_deferred", 0444, NULL, NULL,
+			    &deferred_devs_fops);
 
 	driver_deferred_probe_enable = true;
 	driver_deferred_probe_trigger();
···
 
 static void __exit deferred_probe_exit(void)
 {
-	debugfs_remove_recursive(deferred_devices);
+	debugfs_remove_recursive(debugfs_lookup("devices_deferred", NULL));
 }
 __exitcall(deferred_probe_exit);