RDMA/ocrdma: Set event's device member in ocrdma_dispatch_ibevent()

We need to set ib_evt.device, or else ib_dispatch_event() will crash
when we call it for unaffiliated events (and consumers may get
confused in their QP/CQ/SRQ event handler for affiliated events).

Also fix sparse warning:

    drivers/infiniband/hw/ocrdma/ocrdma_hw.c:678:36: warning: Using plain integer as NULL pointer

There's no need to clear ib_evt, since every member is initialized.
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/ocrdma/ocrdma_hw.c

@@ -675,7 +675,7 @@ static void ocrdma_dispatch_ibevent(struct ocrdma_dev *dev,
 {
 	struct ocrdma_qp *qp = NULL;
 	struct ocrdma_cq *cq = NULL;
-	struct ib_event ib_evt = { 0 };
+	struct ib_event ib_evt;
 	int cq_event = 0;
 	int qp_event = 1;
 	int srq_event = 0;
@@ -688,6 +688,8 @@ static void ocrdma_dispatch_ibevent(struct ocrdma_dev *dev,
 	if (cqe->cqvalid_cqid & OCRDMA_AE_MCQE_CQVALID)
 		cq = dev->cq_tbl[cqe->cqvalid_cqid & OCRDMA_AE_MCQE_CQID_MASK];
 
+	ib_evt.device = &dev->ibdev;
+
 	switch (type) {
 	case OCRDMA_CQ_ERROR:
 		ib_evt.element.cq = &cq->ibcq;