[Proposal] Refactor the remaining helpers out of the diplomacy module in rocket-chip.

**Type of issue**: other enhancement

**Impact**: API modification

**Development Phase**: proposal

refactor freechips.rocketchip.diplomacy to move remaining old diplomacy helpers out to other modules or to the utils module.

Start by auditing the freechips.rocketchip.diplomacy module to identify the remaining old diplomacy helpers and their callers. Determine suitable destination modules or the utils module, then review the API impact and project tests before considering the refactor complete.

Written by the indexing model from the issue text.