net: ethernet: mtk_eth_soc: enable XDP support just for MT7986 SoC

Disable page_pool/XDP support for MT7621 SoC in order fix a regression
introduce adding XDP for MT7986 SoC. There is no a real use case for XDP
on MT7621 since it is a low-end cpu. Moreover this patch reduces the
memory footprint.
Tested-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Fixes: 23233e57 ("net: ethernet: mtk_eth_soc: rely on page_pool for single page buffers")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/2bf31e27b888c43228b0d84dd2ef5033338269e2.1663074002.git.lorenzo@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -1458,7 +1458,7 @@ static void mtk_update_rx_cpu_idx(struct mtk_eth *eth)
 
 static bool mtk_page_pool_enabled(struct mtk_eth *eth)
 {
-	return !eth->hwlro;
+	return MTK_HAS_CAPS(eth->soc->caps, MTK_NETSYS_V2);
 }
 
 static struct page_pool *mtk_create_page_pool(struct mtk_eth *eth,