[Dev] fail to dump value from coprocessor in ARMv8 by openocd

Hi Philip & Peter,

I found there's the limitation on dumping coprocessor value on armv8. My platform is hikey.

I found there're "hi6220.cpu" and "arm" commands in openocd. But I failed to dump any coprocessor value by these commands. After checking the sourcecode, I found that they're just used to dump ARMv4 -- ARMv7. And there's no really support in ARMv8 to dump coprocessor. Do you plan to enable this feature on ARMv8?

Best Regards Haojian