Cleanup after mechanism for marking a compilation option as private

[gilles-peskine-arm]

This is a cleanup task after the main feature of #10147 is done.

• Mechanism to error out on removed configuration options mbedtls-framework#164 adds an entry to make_generated_files.py which has to be conditional until both consuming repositories create the script. Make it unconditional.
• Remove the inclusion of limits.h from tf-psa-crypto/build_info.h, once all repositories have #include <limits.h> everywhere they should.

(More stuff may be added during development.)