nvtop will wake dGPUs not in use

[Mario Limonciello]

Currently when running nvtop it will always wake up ALL GPUs on the system. This makes it difficult on mobile systems that offer multiple GPUs to use NVTOP to profile.

I'd like to ask if you can modify nvtop to not open up the dri render node when the sysfs power/runtime_status file has anything but active in it. You could instead use udev or pciids.txt to show "basic" information about the GPU and a string indicating it's currently in a low power state and instead poll power/runtime_status to tell when it's active again.

[QwertyChouskie]

This is a duplicate of #230

[Mario Limonciello]

Thanks!