target/sh4: Use generic cpu_list()

target/sh4: Use generic cpu_list()

Before it's applied:

[gshan@gshan q]$ ./build/qemu-system-sh4 -cpu ?
sh7750r
sh7751r
sh7785

After it's applied:

[gshan@gshan q]$ ./build/qemu-system-sh4 -cpu ?
Available CPUs:
  sh7750r
  sh7751r
  sh7785

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: <20231114235628.534334-20-gshan@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>