target/xtensa: Use generic cpu_list()

target/xtensa: Use generic cpu_list()

Before it's applied:

[gshan@gshan q]$ ./build/qemu-system-xtensa -cpu ?
Available CPUs:
  test_mmuhifi_c3
  sample_controller
  lx106
  dsp3400
  de233_fpu
  de212
  dc233c
  dc232b

After it's applied:

[gshan@gshan q]$ ./build/qemu-system-xtensa -cpu ?
Available CPUs:
  dc232b
  dc233c
  de212
  de233_fpu
  dsp3400
  lx106
  sample_controller
  test_mmuhifi_c3

Signed-off-by: Gavin Shan <gshan@redhat.com>
Message-ID: <20231114235628.534334-22-gshan@redhat.com>
[PMD: Split patch in 2, only include the "Use generic cpu_list" change]
Message-ID: <51ffd060-b2f8-405c-83e1-a0663c0183f5@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>