Use the number of devices returned by ibv_get_device_list() instead of
stopping at 4.
While we're here, drop the unused MAX_SESSIONS_PER_DEVICE definition
too.
Change-Id: I21ca6c6c95b7f2cccc1de4d0a34b95217a522bfc
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>