rtc: remove redundant of_match_ptr()

Signed-off-by: Zhu Wang <wangzhu9@huawei.com>
Link: https://lore.kernel.org/r/20230808115213.154377-2-wangzhu9@huawei.com
Link: https://lore.kernel.org/r/20230808115213.154377-3-wangzhu9@huawei.com
Link: https://lore.kernel.org/r/20230808115213.154377-4-wangzhu9@huawei.com
Link: https://lore.kernel.org/r/20230808115213.154377-5-wangzhu9@huawei.com
Link: https://lore.kernel.org/r/20230808115213.154377-6-wangzhu9@huawei.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>