Miscellaneous cleanups in X86:
- 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.