[][kernel][mt7988][eth][Correct phy-mode for the USXGMII]

[Description]
Change DTS phy-mode to USXGMII instead of 10GKR except for SFP+.

According to the PHY specification, DE suggests chaning phy-mode
to USXGMII which connects with external 10G PHY.

[Release-log]
N/A


Change-Id: Ic51df5d1ee6ecf1ef572b28f3551a3450481e0ed
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7289672
diff --git a/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7988c-dsa-10g-spim-nand.dts b/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7988c-dsa-10g-spim-nand.dts
index bef96d4..82e0d11 100644
--- a/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7988c-dsa-10g-spim-nand.dts
+++ b/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7988c-dsa-10g-spim-nand.dts
@@ -342,7 +342,7 @@
 		phy-mode = "10gbase-kr";
 
 		fixed-link {
-			speed = <2500>;
+			speed = <10000>;
 			full-duplex;
 			pause;
 		};
@@ -352,7 +352,7 @@
 		compatible = "mediatek,eth-mac";
 		reg = <1>;
 		mac-type = "xgdm";
-		phy-mode = "10gbase-kr";
+		phy-mode = "usxgmii";
 		phy-handle = <&phy0>;
 	};