net: xilinx: axienet: fix potential memory leak in axienet_start_xmit()

The axienet_start_xmit() returns NETDEV_TX_OK without freeing skb
in case of dma_map_single() fails, add dev_kfree_skb_any() to fix it.

Fixes: 71791dc8 ("net: axienet: Check for DMA mapping errors")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Link: https://patch.msgid.link/20241014143704.31938-1-wanghai38@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -1051,6 +1051,7 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 		if (net_ratelimit())
 			netdev_err(ndev, "TX DMA mapping error\n");
 		ndev->stats.tx_dropped++;
+		dev_kfree_skb_any(skb);
 		return NETDEV_TX_OK;
 	}
 	desc_set_phys_addr(lp, phys, cur_p);
@@ -1071,6 +1072,7 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 			ndev->stats.tx_dropped++;
 			axienet_free_tx_chain(lp, orig_tail_ptr, ii + 1,
 					      true, NULL, 0);
+			dev_kfree_skb_any(skb);
 			return NETDEV_TX_OK;
 		}
 		desc_set_phys_addr(lp, phys, cur_p);