net: altera-tse: fix skb leak on DMA mapping error in tse_start_xmit()

When dma_map_single() fails in tse_start_xmit(), the function returns
NETDEV_TX_OK without freeing the skb. Since NETDEV_TX_OK tells the
stack the packet was consumed, the skb is never freed, leaking memory
on every DMA mapping failure.

Add dev_kfree_skb_any() before returning to properly free the skb.

Fixes: bbd2190 ("Altera TSE: Add main and header file for Altera Ethernet Driver")
Cc: stable@vger.kernel.org
Signed-off-by: David Carlier <devnexen@gmail.com>
Link: https://patch.msgid.link/20260401211218.279185-1-devnexen@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: devnexen

drivers/net/ethernet/altera/altera_tse_main.c

@@ -570,6 +570,7 @@ static netdev_tx_t tse_start_xmit(struct sk_buff *skb, struct net_device *dev)
 				  DMA_TO_DEVICE);
 	if (dma_mapping_error(priv->device, dma_addr)) {
 		netdev_err(priv->dev, "%s: DMA mapping error\n", __func__);
+		dev_kfree_skb_any(skb);
 		ret = NETDEV_TX_OK;
 		goto out;
 	}