hw/core/machine: Display CPU model name in 'info cpus' command

Display the CPU model in 'info cpus'. Example before:

 $ qemu-system-aarch64 -M xlnx-versal-virt -S -monitor stdio
 QEMU 10.0.0 monitor - type 'help' for more information
 (qemu) info cpus
 * CPU #0: thread_id=42924
   CPU #1: thread_id=42924
   CPU #2: thread_id=42924
   CPU #3: thread_id=42924
 (qemu) q

and after:

 $ qemu-system-aarch64 -M xlnx-versal-virt -S -monitor stdio
 QEMU 10.0.50 monitor - type 'help' for more information
 (qemu) info cpus
 * CPU #0: thread_id=42916 model=cortex-a72
   CPU #1: thread_id=42916 model=cortex-a72
   CPU #2: thread_id=42916 model=cortex-r5f
   CPU #3: thread_id=42916 model=cortex-r5f
 (qemu)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Tested-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20250715090624.52377-3-philmd@linaro.org>