usb: dwc3: gadget: fix race when disabling ep with cancelled xfers

[ Upstream commit d8eca64e ]

When disabling an endpoint which has cancelled requests, we should
make sure to giveback requests that are currently pending in the
cancelled list, otherwise we may fall into a situation where command
completion interrupt fires after endpoint has been disabled, therefore
causing a splat.

Fixes: fec9095b

 "usb: dwc3: gadget: remove wait_end_transfer"
Reported-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Link: https://lore.kernel.org/r/20191031090713.1452818-1-felipe.balbi@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>