atusb/fw2/ep0.c: make commands needed for sending work
atusb/fw2/ep0.c: make commands needed for sending work

- ep0.c (do_usb_recv, usb_recv): implemented creepy buffer reception
- ep0.c (my_setup): added dummy for ATUSB_POLL_INT (always return 0)
- ep0.c (my_setup): send a zero-length packet at the end of
  ATUSB_RF_RESET and ATUSB_REG_WRITE to indicate status stage

cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan