iio: accel: kxsd9: Switch from linux/of.h to linux/mod_devicetable.h

The only of specific definition used is of_device_id table and that
is found in mod_devicetable.h not of.h
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240218173323.1023703-8-jic23@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/accel/kxsd9-spi.c

 // SPDX-License-Identifier: GPL-2.0-only
 #include <linux/device.h>
 #include <linux/kernel.h>
-#include <linux/of.h>
 #include <linux/spi/spi.h>
 #include <linux/module.h>
+#include <linux/mod_devicetable.h>
 #include <linux/slab.h>
 #include <linux/regmap.h>