target/m68k: Use generic cpu_list()

target/m68k: Use generic cpu_list()

Before it's applied:

[gshan@gshan q]$ ./build/qemu-system-m68k -cpu ?
cfv4e
m5206
m5208
m68000
m68010
m68020
m68030
m68040
m68060
any

After it's applied:

[gshan@gshan q]$ ./build/qemu-system-m68k -cpu ?
Available CPUs:
  any
  cfv4e
  m5206
  m5208
  m68000
  m68010
  m68020
  m68030
  m68040
  m68060

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20231114235628.534334-15-gshan@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>