Fix CQE expansion of unsignaled WQE -- don't expand the CQE when the
WQE index of the completed CQE matches with last pending WQE (tail) in
the queue.
Signed-off-by: NParav Pandit <parav.pandit@emulex.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>