man: mention CQs in fi_endpoint(3)

The fi_endpoint man page wasn't distinguishing between CQs and EQs
per our recent change. The data transfer completions now appear in
CQs not EQs. Passive endpoints need EQs, but not active endpoints.

Signed-off-by: Sayantan Sur <sayantan.sur@intel.com>
Merge pull request #248 from sayantansur/fi-man-endpoint

man: mention CQs in fi_endpoint(3)