[vxge] Fix use of stale I/O buffer on error path

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/vxge/vxge_traffic.c

 		vxge_debug(VXGE_INFO, "%s: rx frame received at offset %d\n",
 			hldev->ndev->name, ring->rxd_offset);
 
+		iobuf = (struct io_buffer *)(intptr_t)rxd->host_control;
+
 		if (tcode != VXGE_HW_RING_T_CODE_OK) {
 			netdev_rx_err(hldev->ndev, NULL, -EINVAL);
 			vxge_debug(VXGE_ERR, "%s:%d, rx error tcode %d\n",
 			goto err1;
 		}
 
-		iobuf = (struct io_buffer *)(intptr_t)rxd->host_control;
-
 		len = VXGE_HW_RING_RXD_1_BUFFER0_SIZE_GET(rxd->control_1);
 		len -= ETH_FCS_LEN;