RDMA/cxgb3: Fix information leak in send_abort()

The cpl_abort_req struct has several reserved members which need to be
cleared to avoid disclosing kernel information.  I have added a memset()
so now it matches the cxgb4 version of this function.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>