arm64: tegra: Add Tegra234 TCU device

Add a device for TCU (Tegra Combined UART) used for serial console.
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm64/boot/dts/nvidia/tegra234.dtsi

@@ -192,6 +192,14 @@ psci {
 		method = "smc";
 	};
 
+	tcu: serial {
+		compatible = "nvidia,tegra234-tcu", "nvidia,tegra194-tcu";
+		mboxes = <&hsp_top0 TEGRA_HSP_MBOX_TYPE_SM TEGRA_HSP_SM_RX(0)>,
+			 <&hsp_aon TEGRA_HSP_MBOX_TYPE_SM TEGRA_HSP_SM_TX(1)>;
+		mbox-names = "rx", "tx";
+		status = "disabled";
+	};
+
 	timer {
 		compatible = "arm,armv8-timer";
 		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,