I2C: host perf precise

I2C: host perf precise: a task in TitanBench: A Benchmark for Agentic RTL Design and Verification (Harbor dataset). Test bus performance matches expectation based on configured timing parameters. Verifies SCL frequency during data bytes matches predicted value.

The task

> Test bus performance matches expectation based on configured timing parameters. Verifies SCL frequency during data bytes matches predicted value.

Part of billshockley/titanbench.