RDMA/i40iw: 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: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/i40iw/i40iw_cm.c

@@ -2410,6 +2410,7 @@ static void i40iw_handle_rst_pkt(struct i40iw_cm_node *cm_node,
 	case I40IW_CM_STATE_FIN_WAIT1:
 	case I40IW_CM_STATE_LAST_ACK:
 		cm_node->cm_id->rem_ref(cm_node->cm_id);
+		/* fall through */
 	case I40IW_CM_STATE_TIME_WAIT:
 		cm_node->state = I40IW_CM_STATE_CLOSED;
 		i40iw_rem_ref_cm_node(cm_node);

drivers/infiniband/hw/i40iw/i40iw_hw.c

@@ -410,6 +410,7 @@ void i40iw_process_aeq(struct i40iw_device *iwdev)
 		case I40IW_AE_UDA_XMIT_DGRAM_TOO_LONG:
 		case I40IW_AE_UDA_XMIT_IPADDR_MISMATCH:
 			ctx_info->err_rq_idx_valid = false;
+			/* fall through */
 		default:
 			if (!info->sq && ctx_info->err_rq_idx_valid) {
 				ctx_info->err_rq_idx = info->wqe_idx;

drivers/infiniband/hw/i40iw/i40iw_puda.c

@@ -816,6 +816,7 @@ void i40iw_puda_dele_resources(struct i40iw_sc_vsi *vsi,
 	switch (rsrc->completion) {
 	case PUDA_HASH_CRC_COMPLETE:
 		i40iw_free_hash_desc(rsrc->hash_desc);
+		/* fall through */
 	case PUDA_QP_CREATED:
 		if (!reset)
 			i40iw_puda_free_qp(rsrc);