RDMA/cm: Define new RDMA port space specific to IB

Add RDMA_PS_IB.  XRC QP types will use the IB port space when operating
over the RDMA CM.  For the 'IP protocol' field value, we select 0x3F,
which is listed as being for 'any local network'.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>