[][kernel][common][eth][Add 2500baseT_Full to the mtk_validate for the FS SFP-2.5G-T module]

[Description]
Add 2500baseT_Full to the mtk_validate for the FS SFP-2.5G-T module.

Without this patch, the FS SFP-2.5G-T module cannot link up at 2.5Gbps
because it is unable to advertise 2500baseT/Full.

[Release-log]
N/A


Change-Id: I61cac68bb3b9581731e833bd5218c6a1386e4fea
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/9905717
diff --git a/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 8eb9f85..f90b447 100644
--- a/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -1453,6 +1453,7 @@
 		if (MTK_HAS_CAPS(mac->hw->soc->caps, MTK_SGMII)) {
 			phylink_set(mask, 1000baseT_Full);
 			phylink_set(mask, 1000baseX_Full);
+			phylink_set(mask, 2500baseT_Full);
 			phylink_set(mask, 2500baseX_Full);
 		}
 		if (MTK_HAS_CAPS(mac->hw->soc->caps, MTK_RGMII)) {