Summary

* Move sysctls out of the kern_table array

  This is the final move of ctl_tables into their respective subsystems. Only 5
  (out of the original 50) will remain in kernel/sysctl.c file; these handle
  either sysctl or common arch variables.

  By decentralizing sysctl registrations, subsystem maintainers regain control
  over their sysctl interfaces, improving maintainability and reducing the
  likelihood of merge conflicts.

* docs: Remove false positives from check-sysctl-docs

  Stopped falsely identifying sysctls as undocumented or unimplemented in the
  check-sysctl-docs script. This script can now be used to automatically
  identify if documentation is missing.

* Testing

  All these have been in linux-next since rc3, giving them a solid 3 to 4 weeks
  worth of testing. Additionally, sysctl selftests and kunit were also run
  locally on my x86_64

docs: Downgrade arm64 & riscv from titles to comment

Remove the title string ("====") from under arm64 & riscv and move them
to a commment under the perf_user_access sysctl. They are explanations,
*not* sysctls themselves

This effectively removes these two strings from appearing as not
implemented when the check-sysctl-docs script is run

Signed-off-by: Joel Granados <joel.granados@kernel.org>