staging:iio:accel:adis16220 iio_chan_spec conversion.

I still have numerous issues with this driver and it
needs a substantial rewrite.

Whilst doing this patch at least one bug has been fixed (temp
reading didn't have an address) and a number of missing channel
info elements added.

Untested!
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>