Inconsistency between a parameter name for AsyncFFSynchronizer and FFSynchronizer

[ECP5-PCIe]

The output domain parameter is o_domain for the synchronous one and domain for the asynchronous one

[awygle]

Since we haven't had a release since this was added, can I just fix this, or do I have to handle backwards-compat?

[whitequark]

We can just fix this.

[whitequark]

(But do we want to have o_domain everywhere rather than domain everywhere? I'm not sure...)

[awygle]

Agreed about the uncertainty but we can talk about that at some eventual meeting.

[whitequark]

We decided to use o_domain for AsyncFFSynchronizer on the meeting.