usb: gadget: uvc: Add missing call for additional setup data

Some UVC commands require additional data (non zero uvc->event_length).
Add usb_ep_queue() call, so uvc_function_ep0_complete() can be called
and send received data to the userspace.

Signed-off-by: Petr Cvek <petr.cvek@tul.cz>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>