arm64: tegra: Clarify that P2972-0000 is Jetson Xavier

The official name for the P2972-0000 board is Jetson AGX Xavier
Development Kit. Set that as the model string in the device tree for
clarity.
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm64/boot/dts/nvidia/tegra194-p2972-0000.dts

@@ -4,7 +4,7 @@
 #include "tegra194-p2888.dtsi"
 
 / {
-	model = "NVIDIA Tegra194 P2972-0000 Development Board";
+	model = "NVIDIA Jetson AGX Xavier Development Kit";
 	compatible = "nvidia,p2972-0000", "nvidia,tegra194";
 
 	cbb {