usb(4): Fix for use after free in combination with EVDEV_SUPPORT.

When EVDEV_SUPPORT was introduced, the USB transfers may be running
after the main FIFO is closed. In connection to this a race may appear
which can lead to use-after-free scenarios. Fix this for all FIFO
consumers by initializing and resetting the FIFO queues under the
lock used by the client. Then the client driver will see an empty
queue in all cases a race may appear.

Found by: pho@
MFC after: 1 week
Sponsored by: NVIDIA Networking