net: systemport: fix potential memory leak in bcm_sysport_xmit()

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

Fixes: 80105bef ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC driver")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Link: https://patch.msgid.link/20241014145115.44977-1-wanghai38@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/bcmsysport.c

@@ -1359,6 +1359,7 @@ static netdev_tx_t bcm_sysport_xmit(struct sk_buff *skb,
 		netif_err(priv, tx_err, dev, "DMA map failed at %p (len=%d)\n",
 			  skb->data, skb_len);
 		ret = NETDEV_TX_OK;
+		dev_kfree_skb_any(skb);
 		goto out;
 	}