The previous TD lock-free patch introduced ibv_create_cq_ex() to
perftest, but it breaks the provider devices which do not support
this API yet. For these devices calling this API leads to an errno
of EOPNOTSUPP. So add a check of errno, and if it is EOPNOTSUPP,
use ibv_create_cq() as a fallback.
Fixes: b6f957f ("Perftest: Add support for TD lock-free mode")
(cherry picked from commit c6e2261f2d5be0856a7e2be14ae794a0ef8649df)
