nvidia-modprobe recommendation should be more direct

[puneetse]

Describe the error/improvement to an existing document or image
This is a continuation of a discussion that started in PR #1024.

The nvidia-modprobe utility is required by CUDA based on user reports.

The Clear Linux instructions for installing NVIDIA drivers exclude nvidia-modprobe due to it not obeying installation switches.

The nvidia-cuda doc already provides instructions on how to manually compile nvidia-modprobe makes it sound like a nice-to-have more than a requirement.

Update the nvidia-cuda document to make the installation of nvidia-modprobe a required step.

Additional context
https://docs.01.org/clearlinux/latest/tutorials/nvidia-cuda.html

[puneetse]

If anyone from the community wants to take this edit on, that would be swell!