NVML GSP mode function needs reworked

In 510.68.02, a function was introduced called nvmlDeviceGetGspFirmwareMode. This function has three issues with it:

1. On Linux, it will fill both pointers with zero(false) even on Pascal when it should instead return NVML_ERROR_NOT_SUPPORTED. This is different to what the previous GSP NVML function, nvmlDeviceGetGspFirmwareVersion does and gives users the impression that their GPU has GSP firmware when it does not.

2. On Windows with a Maxwell based GPU, nvmlDeviceGetGspFirmwareMode seems to always return NVML_ERROR_NOT_SUPPORTED, which is different than on Linux and Pascal. If you can't already, it should be possible to get the firmware version even on Windows.

3. NVML_ERROR_NOT_SUPPORTED is returned despite not being documented.

Given that this new kernel driver requires GSP, making sure that it's possible to get reliable information as to whether their GPU has GSP firmware is important. A nvmlDeviceGetGspFirmwareMode_v2 function should be introduced and the old function deprecated to fix these problems.

Start with the nvmlDeviceGetGspFirmwareMode and nvmlDeviceGetGspFirmwareVersion declarations linked in nvml.h, then trace their Linux and Windows implementations for Pascal and Maxwell behavior. Done means a v2 interface reports supported GSP status consistently, documents NVML_ERROR_NOT_SUPPORTED, and leaves the old function deprecated.