Add check for valid nvidia_smi output

[themadprofessor]

When the nvidia driver is updated and the new module hasn't been loaded, nvidia-smi can produce invalid output such as "Failed to initialize NVML: Driver/library version mismatch", which can cause a panic.
This adds a check to ensure the output from nvidia-smi contains at least 2 commas.

[ammgws]

Is the exit status non-zero in that situation? Perhaps you could catch that instead.

[themadprofessor]

That it does, shall change it to check for that.

[ammgws]

I don't have a way to test this so I hope it's OK.

Thanks!