net: netsec: Correct dma sync for XDP_TX frames

bpf_xdp_adjust_head() can change the frame boundaries. Account for the
potential shift properly by calculating the new offset before
syncing the buffer to the device for XDP_TX

Fixes: ba2b2321 ("net: netsec: add XDP support")
Signed-off-by: NIlias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/socionext/netsec.c

@@ -847,8 +847,8 @@ static u32 netsec_xdp_queue_one(struct netsec_priv *priv,
 		enum dma_data_direction dma_dir =
 			page_pool_get_dma_dir(rx_ring->page_pool);
 
-		dma_handle = page_pool_get_dma_addr(page) +
-			NETSEC_RXBUF_HEADROOM;
+		dma_handle = page_pool_get_dma_addr(page) + xdpf->headroom +
+			sizeof(*xdpf);
 		dma_sync_single_for_device(priv->dev, dma_handle, xdpf->len,
 					   dma_dir);
 		tx_desc.buf_type = TYPE_NETSEC_XDP_TX;