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 <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

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>