rtc: ds1302: remove unnecessary spi_set_drvdata()

Remove unnecessary spi_set_drvdata() in ds1302_remove(), the driver_data
will be set to NULL in device_unbind_cleanup() after calling ->remove().
After this, ds1302_remove() is an empty function, so remove it too.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220913144905.2004924-1-yangyingliang@huawei.com


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