arm64: tegra: Enable debug serial on Jetson TX1

Add a chosen node to the device tree that contains a stdout-path
property which defines the debug serial port.
Signed-off-by: NThierry Reding <treding@nvidia.com>

arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi

@@ -12,6 +12,10 @@
 		serial0 = &uarta;
 	};
 
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
 	memory {
 		device_type = "memory";
 		reg = <0x0 0x80000000 0x1 0x0>;