arm64: dts: mt7622: fix no more console output on BPI-R64 board

Fix this by using a 'stdout-path' property that points to the device.

Fixes: 0b6286dd96c0 ("arm64: dts: mt7622: add bananapi BPI-R64 board")
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt7622-bananapi-bpi-r64.dts

@@ -16,8 +16,13 @@
 	model = "Bananapi BPI-R64";
 	compatible = "bananapi,bpi-r64", "mediatek,mt7622";
 
+	aliases {
+		serial0 = &uart0;
+	};
+
 	chosen {
-		bootargs = "earlycon=uart8250,mmio32,0x11002000 console=ttyS0,115200n1 swiotlb=512";
+		stdout-path = "serial0:115200n8";
+		bootargs = "earlycon=uart8250,mmio32,0x11002000 swiotlb=512";
 	};
 
 	cpus {