If ocrdma_get_pd_num() fails, then we need to free the pd struct we allocated.

This was detected by Coverity (CID 1271245).
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Acked-By: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>