Improve "How do I reinstall Lambda Stack in Ubuntu on my Tensorbook?"

[cbrownstein-lambda]

For: https://update-list-top-faqs.lambda-docs.pages.dev/tensorbook/reinstall-lambda-stack/
Yours should be included in Lambda Stack. But I noticed these as additional differences between AMD desktop/tensorbook
Also I think the iommu=soft we may be able to remove (with a bit more testing), which would save headaches on 256 hyperthread CPUs. (It confused Kubernetes, and slurm you need to modify configs to deal with only 255 seen one thread would be disabled on iommu=soft).
I have for the various tensorbooks/workstations in the QA scripts:
if is_desktop_amd; then
run_test "Checking for software IOMMU on Desktop AMD" "grep "iommu=soft" /proc/cmdline"
fi
if is_tensorbook2; then
run_test "Tensorbook ACPI options set" "grep "acpi_os_name=Linux acpi_osi= acpi_backlight=vendor" /proc/cmdline"
fi
if is_tensorbook4; then
run_test "Tensorbook keyboard fix set" "grep "i8042.nomux" /proc/cmdline"
fi
if is_tensorbook; then
run_test "Tensorbook TTY resolution set" "grep "video=1920x1080" /proc/cmdline"
fi

Credit: @markwdalton