The npcm7xx Soc is created with a Cortex-A9 core, see in
hw/arm/npcm7xx.c:

  static void npcm7xx_init(Object *obj)
  {
      NPCM7xxState *s = NPCM7XX(obj);

      for (int i = 0; i < NPCM7XX_MAX_NUM_CPUS; i++) {
          object_initialize_child(obj, "cpu[*]", &s->cpu[i],
                                  ARM_CPU_TYPE_NAME("cortex-a9"));
      }

The MachineClass::default_cpu_type field is ignored: delete it.

Use the common code introduced in commit c9cf636d48 ("machine: Add
a valid_cpu_types property") to check for valid CPU type at the
board level.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/arm/npcm7xx_boards.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/hw/arm/npcm7xx_boards.c b/hw/arm/npcm7xx_boards.c
index 2aef579aac..98f9af27e7 100644
--- a/hw/arm/npcm7xx_boards.c
+++ b/hw/arm/npcm7xx_boards.c
@@ -121,15 +121,8 @@ static NPCM7xxState *npcm7xx_create_soc(MachineState *machine,
                                         uint32_t hw_straps)
 {
     NPCM7xxMachineClass *nmc = NPCM7XX_MACHINE_GET_CLASS(machine);
-    MachineClass *mc = MACHINE_CLASS(nmc);
     Object *obj;
 
-    if (strcmp(machine->cpu_type, mc->default_cpu_type) != 0) {
-        error_report("This board can only be used with %s",
-                     mc->default_cpu_type);
-        exit(1);
-    }
-
     obj = object_new_with_props(nmc->soc_type, OBJECT(machine), "soc",
                                 &error_abort, NULL);
     object_property_set_uint(obj, "power-on-straps", hw_straps, &error_abort);
@@ -462,13 +455,17 @@ static void npcm7xx_set_soc_type(NPCM7xxMachineClass *nmc, const char *type)
 
 static void npcm7xx_machine_class_init(ObjectClass *oc, void *data)
 {
+    static const char *machine_valid_cpu_types[] = {
+        ARM_CPU_TYPE_NAME("cortex-a9"),
+        NULL
+    };
     MachineClass *mc = MACHINE_CLASS(oc);
 
     mc->no_floppy = 1;
     mc->no_cdrom = 1;
     mc->no_parallel = 1;
     mc->default_ram_id = "ram";
-    mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-a9");
+    mc->valid_cpu_types = machine_valid_cpu_types;
 }
 
 /*
-- 
2.41.0