Optimise host mode data roundtrip time. When BULK data is submitted to
the main processing queue, clear the NAK counter for any associated
BULK or CONTROL transfers and poll the endpoint(s) for 1 millisecond
at 125us rate interval, before going into slow, 10ms, NAK polling mode
again.  This has the effect that typical ping-ping protocols respond
quicker when initiated from the USB host.

MFC after:	2 weeks