can call libcxl function outside ndctl tool?

[Li Qiang]

Take cxl_cmd_new_identify as example.
There is CXL_EXPORT prefix, it seems can be called outside ndctl tool.
While the intput and outpust struct cxl_memdev and cxl_cmd are private.

```

CXL_EXPORT struct cxl_cmd *cxl_cmd_new_identify(struct cxl_memdev *memdev)
{
        return cxl_cmd_new_generic(memdev, CXL_MEM_COMMAND_ID_IDENTIFY);
}

```


Thanks
Johnny