[ofw] [RFC] [2/2] ib cm: export CM only interface

[Sean Hefty]

>> -               p_cep->pfn_cb = pfn_cb;
>> +               p_cep->pfn_cb = pfn_cb ? pfn_cb : p_cep->pfn_cb;
>
>This makes it impossible for a client to clear the callback of a CEP created in
>response to a REQ received on a callback-driven listening CEP.  I think if you
>want to leave the value unchanged you should have a special value reserved -
>NULL is a valid callback pointer for the CEP.

The change here is to combine two nearly identical blocks of code into one
(al_cep_pre_rep and al_cep_pre_rep_ex).  I needed a third block and
al_cep_pre_rep_ex_ex just seemed ridiculous.  al_cep_pre_rep() is only called
from al_cm_qp.c, which doesn't modify the callback.

- Sean