virtio: console: remove unnecessary null test before debugfs_remove_recursive

Fix checkpatch warning:
WARNING: debugfs_remove_recursive(NULL) is safe this check is probably not required

Cc: Arnd Bergmann <[e-mail]>
Cc: [e-mail]
Reviewed-by: Amit Shah <[e-mail]>
Signed-off-by: Fabian Frederick <[e-mail]>
Signed-off-by: Rusty Russell <[e-mail]>

drivers/char/virtio_console.c

···
 unregister:
 	unregister_virtio_driver(&virtio_console);
 free:
-	if (pdrvdata.debugfs_dir)
-		debugfs_remove_recursive(pdrvdata.debugfs_dir);
+	debugfs_remove_recursive(pdrvdata.debugfs_dir);
 	class_destroy(pdrvdata.class);
 	return err;
 }
···
 	unregister_virtio_driver(&virtio_rproc_serial);
 
 	class_destroy(pdrvdata.class);
-	if (pdrvdata.debugfs_dir)
-		debugfs_remove_recursive(pdrvdata.debugfs_dir);
+	debugfs_remove_recursive(pdrvdata.debugfs_dir);
 }
 module_init(init);
 module_exit(fini);