I remember this now.
Original series had three patches, two adding the feature to xhci, and one for dwc3 enabling it.
The xhci patches were fine and got in.
https://marc.info/?l=linux-usb&m=160570849625065&w=2
The last dwc3 patch had issues and never apparently got in
https://marc.info/?l=linux-usb&m=161008968009766&w=2
As this feature hasn't been enabled and code not widely run I think it would be better
to skip stable for now. Stable can be added later once this has been successfully running
in upstream for a while.
Thanks
Mathias