char: xillybus: Use to_delayed_work()

Use to_delayed_work() instead of open-coding it.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Acked-by: Eli Billauer <eli.billauer@gmail.com>
Link: https://lore.kernel.org/r/20250414074559.3954142-1-nichen@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Chen Ni

drivers/char/xillybus/xillybus_core.c

@@ -1184,8 +1184,7 @@ static int xillybus_flush(struct file *filp, fl_owner_t id)
 
 static void xillybus_autoflush(struct work_struct *work)
 {
-	struct delayed_work *workitem = container_of(
-		work, struct delayed_work, work);
+	struct delayed_work *workitem = to_delayed_work(work);
 	struct xilly_channel *channel = container_of(
 		workitem, struct xilly_channel, rd_workitem);
 	int rc;