x86-cleanups-2023-02-20

  - Correct the common copy and pasted mishandling of kstrtobool() in the
    strict_sas_size() setup function.

  - Make recalibrate_cpu_khz() an GPL only export.

  - Check TSC feature before doing anything else which avoids pointless
    code execution if TSC is not available.

  - Remove or fixup stale and misleading comments.

  - Remove unused or pointelessly duplicated variables.

  - Spelling and typo fixes.