[ewg] rdma/cm: disallow loopback address for iwarp devices

[Sean Hefty]

>On my OFED 1.4.1 RHEL4u6 systems, rdma_bind_addr() fails when attempting to
>bind to 127.0.0.1 per the email I sent Friday:
>
>    http://www.spinics.net/lists/linux-rdma/msg02568.html

This is what I see over IB on 2.6.26, with a couple extra prints added to
cmatose:

cst-lin1:/home/mshefty/librdmacm# examples/ucmatose -b 127.0.0.1
cmatose: starting server
src addr 0x100007f
rdma_bind_addr: 0

so we're missing something else.