CODEOWNERS: fix 3 check-compliance.py issues not reported by github

- PR #13722 moved 3 gen_*.py to /arch/x86/ without updating CODEOWNERS
- PR #13745 forgot a trailing slash in /dts/bindings/can
- PR #13675 forgot a trailing slash in /samples/boards/intel_s1000_crb

No idea why github doesn't keep reporting these every time and
impossible to tell as CI hides most of its logs.

Signed-off-by: Marc Herbert <marc.herbert@intel.com>