[reggen] Error check for data-intg-passthrough

[tjaychen]

The reggen supports an option called data-intg-passthrough on windowed regions.
If this variable is true, it basically means beyond the window region there is already data integrity, thus the data integrity should not be generated for it in reg_top (the integrity for registers will instead be moved to tlul_adapter_reg).

Having said that, the current scripting does not really handle / check the case if a reg block has multiple windows each with different expectations on data-intg-passthrough. We do not have this case right now, but it would be good to explicitly add an error check to ensure all windows either agree or disagree.

[tjaychen]

@rswarbrick
@msfschaffner
@eunchan

[rswarbrick]

And/or teach the generated RTL to handle the mixed case properly. But I agree: that will probably never be used, so it's probably a better idea to mandate one or the other.

[msfschaffner]

Agreed. If we do not want to handle mixed cases in RTL (or don't have the time to implement that), let's just add a check for this.

[andreaskurth]

Triaged for tlul. Keeping Type:FutureRelease Not relevant to currently planned releases/milestones because we don't make use of this in the current design (as per the issue description).