Fix ib_iser build to depend on INFINIBAND_ADDR_TRANS; if INET=y but
IPV6=n, then the RDMA CM is not built but INFINIBAND_ISER can be
enabled, leading to:

    ERROR: "rdma_destroy_id" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_connect" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_destroy_qp" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_create_id" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_create_qp" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_resolve_route" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_disconnect" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_resolve_addr" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>