staging: iio: accel: adis16240: Replace 'unsigned' with 'unsigned int'

Replace 'unsigned' with 'unsigned int' to avoid checkpatch warning.

Signed-off-by: Svetlana Orlik <sveta.orlik.code@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>