RDMA/core: Initialize port_num in qp_attr

RDMA/core: Initialize port_num in qp_attr

commit a62ab66b13a0f9bcb17b7b761f6670941ed5cd62 upstream.

Initialize the port_num for iWARP in rdma_init_qp_attr.

Fixes: 5ecce4c9b17b("Check port number supplied by user verbs cmds")
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Mustafa Ismail <mustafa.ismail@intel.com>
Tested-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>