net: axienet: fix a potential double free in axienet_probe()

There is a possible use-after-free issue in the axienet_probe():

1701:	np = of_parse_phandle(pdev->dev.of_node, "axistream-connected", 0);
1702:   if (np) {
...
1787:		of_node_put(np); ---> released here
1788:		lp->eth_irq = platform_get_irq(pdev, 0);
1789:	} else {
...
1801:	}
1802:	if (IS_ERR(lp->dma_regs)) {
...
1805:		of_node_put(np); ---> double released here
1806:		goto free_netdev;
1807:	}

We solve this problem by removing the unnecessary of_node_put().

Fixes: 28ef9eb ("net: axienet: make use of axistream-connected attribute optional")
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Cc: Anirudha Sarangi <anirudh@xilinx.com>
Cc: John Linn <John.Linn@xilinx.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Robert Hancock <hancock@sedsystems.ca>
Cc: netdev@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Robert Hancock <hancock@sedsystems.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -1802,7 +1802,6 @@ static int axienet_probe(struct platform_device *pdev)
 	if (IS_ERR(lp->dma_regs)) {
 		dev_err(&pdev->dev, "could not map DMA regs\n");
 		ret = PTR_ERR(lp->dma_regs);
-		of_node_put(np);
 		goto free_netdev;
 	}
 	if ((lp->rx_irq <= 0) || (lp->tx_irq <= 0)) {