raw/ioat: fix kvlist free

raw/ioat: fix kvlist free

There is a null pointer check in 'idxd_vdev_parse_params()' which is
causing a coverity issue. This check is redundant as the same check is
being done in 'rte_kvargs_free()', so it is simply removed in this patch.

In addition, kvlist was only being free'd on one path in this function.
This is fixed by always free'ing kvlist before returning.

Coverity issue: 363049
Fixes: 777edf43ae4f ("raw/ioat: introduce vdev probe for DSA/idxd device")

Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>