pds_core: Fix up some minor issues

Running xmastree.py against the driver found some
RCT issues, so fix them.

Also, if allocating pdsc->intr_info in pdsc_dev_init()
fails the driver still tries to free pdsc->intr_info.
Fix this by just returning -ENOMEM since there's
nothing to free at this point of failure.

Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>