fi_ep_bind: correct fi_ep_bind type

Correct manpage fi_ep_bind ignature:

int fi_ep_bind(struct fid *ep, struct fid *fid, uint64_t flags);

TO:

int fi_ep_bind(struct fid_ep *ep, struct fid *fid, uint64_t flags);

Provide static inline implementation of fi_ep_bind that does
type-checking.

Signed-off-by: Sayantan Sur <sayantan.sur@intel.com>