Revert "usb: gadget: composite: dequeue cdev->req before free its buffer"

This reverts commit be0a8887.

The original commit f2267089
(usb: gadget: composite: dequeue cdev->req before free it in
composite_dev_cleanup) ended up being reverted because it caused
more issues then fixed. We will also revert this counter part
commit so we start clean to properly add that idea back.

Cc: Li Jun <b47624@freescale.com>
Signed-of-by: Felipe Balbi <balbi@ti.com>