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

[Sean Hefty]

>At least this area of the code needs work.  I will move iba_cm_id into a larger
>structure that contains an event that gets signaled by a destroy callback.
>cm_destroy_id() will wait on that event before freeing p_id.
>
>The other place where al_destroy_cep() is called should be fine, since it's
>inside the callback for the listen.

I also added a wrapper around al_destroy_cep() -- kal_destroy_cep() -- to allow
specifying the destroy callback when, er.., calling destroy!  I don't understand
how the existing interfaces work if the user rejects a REQ, since they can't
ever specify the destroy callback.