usb: gadget: composite: set our req->context to cdev
usb: gadget: composite: set our req->context to cdev

by doing that we will be able to match our
requests against req and os_desc_req and also
clear our pending flags from complete callback.

Signed-off-by: Felipe Balbi <94dddeeef08b001e003cce128ddc162a4e2c6cd2@ti.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs