hw/cpu: Clean up global variable shadowing

hw/cpu: Clean up global variable shadowing

Fix:

  hw/core/machine.c:1302:22: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
      const CPUArchId *cpus = possible_cpus->cpus;
                       ^
  hw/core/numa.c:69:17: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
      uint16List *cpus = NULL;
                  ^
  hw/acpi/aml-build.c:2005:20: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
      CPUArchIdList *cpus = ms->possible_cpus;
                     ^
  hw/core/machine-smp.c:77:14: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
      unsigned cpus    = config->has_cpus ? config->cpus : 0;
               ^
  include/hw/core/cpu.h:589:17: note: previous declaration is here
  extern CPUTailQ cpus;
                  ^

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Message-Id: <20231010115048.11856-2-philmd@linaro.org>