usb: add shortcut for control transfers

Add a more direct code path to submit control transfers.  Instead of
feeding three usb packets (setup, data, ack) to usb_handle_packet and
have the do_token_* functions in usb.c poke the control transfer
parameters out of it just submit a single packet carrying the actual
data with the control xfer parameters filled into USBPacket->parameters.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>