rtc: ds1343: Remove unused struct spi_device in struct ds1343_priv

rtc: ds1343: Remove unused struct spi_device in struct ds1343_priv

struct spi_device in struct ds1343_priv is not used, remove it.

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Alexandre Belloni <alexandre.belloni@bootlin.com>
CC: Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
CC: Ankur Srivastava <sankurece@gmail.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Link: https://lore.kernel.org/r/20191218081917.3308211-1-iwamatsu@nigauri.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>