staging:iio:adis16260: Remove unused includes

Remove some unused includes from the driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/gyro/adis16260_core.c

@@ -7,15 +7,11 @@
  */
 
 #include <linux/interrupt.h>
-#include <linux/irq.h>
-#include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/spi/spi.h>
-#include <linux/slab.h>
 #include <linux/sysfs.h>
-#include <linux/list.h>
 #include <linux/module.h>
 
 #include <linux/iio/iio.h>