UPSTREAM: usb: dwc3: gadget: give better command return code

UPSTREAM: usb: dwc3: gadget: give better command return code

if Start Transfer command fails, let's try a little
harder to figure out why the command failed and give
slightly better return codes. This will be usefulf
or isochronous endpoints, at least, which could
decide to retry a given request.

Change-Id: Id3ce609ba9149235dc8c9203798dc19cb2fae4bd
Signed-off-by: Konrad Leszczynski <konrad.leszczynski@intel.com>
Signed-off-by: Rafal Redzimski <rafal.f.redzimski@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Wu Liang feng <wulf@rock-chips.com>
(cherry picked from commit 7b9cc7a2b101cc73f6abe3468441381c98817e54)