Initialize the port_num for iWARP in rdma_init_qp_attr.

Fixes: 5ecce4c9("Check port number supplied by user verbs cmds")
Cc: <stable@vger.kernel.org> # v2.6.14+
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NMustafa Ismail <mustafa.ismail@intel.com>
Tested-by: NMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>