raw/ioat: split header file for readability

raw/ioat: split header file for readability

Rather than having a single long complicated header file for general use we
can split things so that there is one header with all the publicly needed
information - data structs and function prototypes - while the rest of the
internal details are put separately. This makes it easier to read,
understand and use the APIs.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Kevin Laatz <kevin.laatz@intel.com>
Acked-by: Radu Nicolau <radu.nicolau@intel.com>