Use the new uart0 label for the console and make the speed explicit by
setting stdout-path = "serial0:115200n8" under /chosen. This keeps the
DTS OS-agnostic: no bootargs or distribution-specific properties are
added.

Drop the 'current-speed' property from uart0 as it is not allowed by the
mediatek UART binding. The baud is already provided via stdout-path.

Verification: Boot-tested with mainline Image+DTB via U-Boot on OpenWrt
One (MT7981B). Serial console active at 115200, DTB decompile
confirms serial0 alias and stdout-path set correctly.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/r/202509211032.0rJjPoYE-lkp@intel.com/
Signed-off-by: Bryan Hinton <bryan@bryanhinton.com>
---
 arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts b/arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts
index 4f6cbb491287..968b91f55bb2 100644
--- a/arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts
+++ b/arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts
@@ -8,8 +8,20 @@ / {
 	compatible = "openwrt,one", "mediatek,mt7981b";
 	model = "OpenWrt One";
 
+	aliases {
+		serial0 = &uart0;
+	};
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
 	memory@40000000 {
 		reg = <0 0x40000000 0 0x40000000>;
 		device_type = "memory";
 	};
 };
+
+&uart0 {
+	status = "okay";
+};
-- 
2.51.0