ibacm: Change base endpoint name

ibacm: Change base endpoint name

Endpoints are given a string identifer (base name) that matches
the first address assigned to the endpoint.  Store the endpoint
string identifier separately from the address name, and identify
the endpoint using the device name, port, and pkey.

The endpoint identifier is only used for logging purposes.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>