RDMA/bnxt_re: Report MISSED_EVENTS in req_notify_cq

While invoking the req_notify_cq hook, ULPs can request
whether the CQs have any CQEs pending. If CQEs are pending,
drivers can indicate  it by returning 1 for req_notify_cq.
The stack will poll CQ again till CQ is empty.

This patch peeks the CQ for any valid entries and return accordingly.

Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>