Check alignment of Ibex bus interface with "OBI" bus standard

The OpenHW group, which continues the development of the ETH/PULP RISCY core as CV32E40P, has published a more complete description of the bus interface that also Ibex uses at https://github.com/openhwgroup/core-v-docs/blob/master/cores/cv32e40p/OBI-v1.0.pdf (no source code or HTML version is available AFAIK). We should check if our interface matches their description, and document compatibility or divergence as needed (at least the reset signal is named differently from what I've seen on a first look).

We also should add a protocol checker to our code base to ensure that we stay compliant with it.

@Silabs-ArjanB do you have a protocol checker in your code base (e.g. something like the one we have in OpenTitan for TL-UL at https://github.com/lowRISC/opentitan/blob/master/hw/ip/tlul/rtl/tlul_assert.sv (docs), or do you have plans for such a module? It would be good if we can share the development effort for such a module.

Start by comparing Ibex's bus interface with the OpenHW OBI-v1.0.pdf description, paying particular attention to the reset signal and other documented divergences. Review the existing OpenTitan TL-UL protocol checker as a reference; done means compatibility or differences are documented and a protocol checker is added to enforce the agreed OBI behavior.