Staging: iio: adis16209: Remove unused headers

Remove few unused header files since the adis core handles
the sysfs and buffer support.
Signed-off-by: Shreeya Patel <shreeya.patel23498@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/accel/adis16209.c

@@ -6,7 +6,6 @@
  * Licensed under the GPL-2 or later.
  */
 
-#include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
@@ -16,8 +15,6 @@
 #include <linux/sysfs.h>
 
 #include <linux/iio/iio.h>
-#include <linux/iio/sysfs.h>
-#include <linux/iio/buffer.h>
 #include <linux/iio/imu/adis.h>
 
 #define ADIS16209_STARTUP_DELAY_MS	220