@parly have you emailed the rockchip kernel list to report the problem. The patch is simple enough that you can see what its doing, just pulling a gpio pin to enable usb. So if this stops usb working its a smoking gun that the schematic for rock64 is incorrect ...
Good that you and Robin got to the bottom of the problem, and have submitted a patch; that should hopefully be accepted, but I guess not before kernel version 5.2.