RDMA/rxe: Suppress gcc 7 fall-through complaints

Avoid that gcc 7 reports the following warning when building with W=1:

warning: this statement may fall through [-Wimplicit-fallthrough=]
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Cc: Moni Shoua <monis@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/sw/rxe/rxe_comp.c

@@ -270,8 +270,8 @@ static inline enum comp_state check_ack(struct rxe_qp *qp,
 		if ((syn & AETH_TYPE_MASK) != AETH_ACK)
 			return COMPST_ERROR;
 
-		/* Fall through (IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE
-		 * doesn't have an AETH)
+		/* fall through */
+		/* (IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE doesn't have an AETH)
 		 */
 	case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
 		if (wqe->wr.opcode != IB_WR_RDMA_READ &&

drivers/infiniband/sw/rxe/rxe_task.c

@@ -71,7 +71,7 @@ void rxe_do_task(unsigned long data)
 
 	case TASK_STATE_BUSY:
 		task->state = TASK_STATE_ARMED;
-		/* fall through to */
+		/* fall through */
 	case TASK_STATE_ARMED:
 		spin_unlock_irqrestore(&task->state_lock, flags);
 		return;

drivers/infiniband/sw/rxe/rxe_verbs.c

@@ -644,6 +644,7 @@ static void init_send_wr(struct rxe_qp *qp, struct rxe_send_wr *wr,
 		switch (wr->opcode) {
 		case IB_WR_RDMA_WRITE_WITH_IMM:
 			wr->ex.imm_data = ibwr->ex.imm_data;
+			/* fall through */
 		case IB_WR_RDMA_READ:
 		case IB_WR_RDMA_WRITE:
 			wr->wr.rdma.remote_addr = rdma_wr(ibwr)->remote_addr;