ANDROID: usb: dwc3: gadget: don't cancel the started requests

Currently, there is an application on Mac that it will send
ClearFeature(halt_ep) request before transfering USB data.

If the device receives the ClearFeature(halt_ep) request, the
started requests would be removed and restart the transfer.
However, userspace services don't know this behavior. The services
will free the requests instead of retry and resend the requests.

It will cause the USB host can't get response so that it will try
to recover by issuing a reset signal.

Finally, it will take the infinite loop.
send reqeust > reset > re-enumeration > send request > reset > ...

To avoid this symptom, this patch will keep the started requests
so that userspace services didn't free the requests.

Bug: 178904115
Bug: 177879761
Signed-off-by: Ray Chi <raychi@google.com>
Change-Id: I52acf48871fd7f86cfcc51fb41c67d21ea895d69
Signed-off-by: Saravana Kannan <saravanak@google.com>