s2io.c: Convert skipped nic->config.tx_cfg[i]. to tx_cfg->

Missed doing the conversion in earlier patch.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Sreenivasa Honnur <sreenivasa.honnur@neterion.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/s2io.c

@@ -1001,7 +1001,7 @@ static void free_shared_mem(struct s2io_nic *nic)
 			swstats->mem_freed += PAGE_SIZE;
 		}
 		kfree(fifo->list_info);
-		swstats->mem_freed += nic->config.tx_cfg[i].fifo_len *
+		swstats->mem_freed += tx_cfg->fifo_len *
 			sizeof(struct list_info_hold);
 	}