hw/arm/exynos: Check for CPU types in machine_run_board_init()

Restrict MachineClass::valid_cpu_types[] to the single
valid CPU type.

Instead of ignoring invalid CPU type requested by the user:

  $ qemu-system-arm -M nuri -cpu cortex-a7 -S -monitor stdio
  QEMU 8.2.50 monitor - type 'help' for more information
  (qemu) info qom-tree
  /machine (nuri-machine)
    /soc (exynos4210)
      /cpu[0] (cortex-a9-arm-cpu)
      ...

We now display an error:

  $ qemu-system-arm -M nuri -cpu cortex-a7
  qemu-system-arm: Invalid CPU model: cortex-a7
  The only valid type is: cortex-a9

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Message-id: 20240129151828.59544-3-philmd@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/exynos4_boards.c

@@ -34,6 +34,7 @@
 #include "hw/qdev-properties.h"
 #include "hw/boards.h"
 #include "hw/irq.h"
+#include "target/arm/cpu-qom.h"
 
 #define SMDK_LAN9118_BASE_ADDR      0x05000000
 
@@ -150,12 +151,18 @@ static void smdkc210_init(MachineState *machine)
     arm_load_kernel(s->soc.cpu[0], machine, &exynos4_board_binfo);
 }
 
+static const char * const valid_cpu_types[] = {
+    ARM_CPU_TYPE_NAME("cortex-a9"),
+    NULL
+};
+
 static void nuri_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
 
     mc->desc = "Samsung NURI board (Exynos4210)";
     mc->init = nuri_init;
+    mc->valid_cpu_types = valid_cpu_types;
     mc->max_cpus = EXYNOS4210_NCPUS;
     mc->min_cpus = EXYNOS4210_NCPUS;
     mc->default_cpus = EXYNOS4210_NCPUS;
@@ -174,6 +181,7 @@ static void smdkc210_class_init(ObjectClass *oc, void *data)
 
     mc->desc = "Samsung SMDKC210 board (Exynos4210)";
     mc->init = smdkc210_init;
+    mc->valid_cpu_types = valid_cpu_types;
     mc->max_cpus = EXYNOS4210_NCPUS;
     mc->min_cpus = EXYNOS4210_NCPUS;
     mc->default_cpus = EXYNOS4210_NCPUS;