clockevents: Use list_move() instead of list_del()/list_add()

Simplify the code.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210609070242.1322450-1-libaokun1@huawei.com