Cannot see PREFERRED_PSTATE_STRING

Hello.

Wondering if it's possible to see PREFERRED_PSTATE_STRING using this library. It's in [NvApiDriverSettings](https://github.com/Kaldaien/ds3t/blob/master/src/nvapi/NvApiDriverSettings.h) and is known as "Power management mode" in the NVIDIA control panel. Interested to be able to see what the value is currently set as on a convig.

Thanks!