fix(morello): dts: add model names

The core root node DT bindings require every DT to have a "model"
property. Linux' "make dtbs_check" reports:
============
.../morello-soc.dt.yaml: /: 'model' is a required property
     From schema: dt-schema.git/dtschema/schemas/root-node.yaml
============

Add a model name to both the SoC and FVP files to improve bindings
compliance.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Change-Id: I64923edb947f8939dfa24c13a37996b1ba34ea54
diff --git a/fdts/morello-soc.dts b/fdts/morello-soc.dts
index f93f980..2f9865b 100644
--- a/fdts/morello-soc.dts
+++ b/fdts/morello-soc.dts
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -8,6 +8,7 @@
 #include "morello.dtsi"
 
 / {
+	model = "Arm Morello System Development Platform";
 
 	chosen {
 		stdout-path = "serial0:115200n8";