staging:iio:accel:adis16203 move buffers into state and use iio_priv to avoid...

staging:iio:accel:adis16203 move buffers into state and use iio_priv to avoid allocating state separately.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>