While Fomu is produced by Foosn, the actual name of the hardware
block is `valentyusb`. Rename the module to match that.
Signed-off-by: Sean Cross <sean@xobs.io>
The Fomu bitstream now includes a `USB_NEXT_EV` register to
indicate which is the next logical event to process. Add this
register to the CSR definition.
Signed-off-by: Sean Cross <sean@xobs.io>