UPSTREAM: usb: dwc2: Fix issues in dwc2_complete_non_isoc_xfer_ddma()

UPSTREAM: usb: dwc2: Fix issues in dwc2_complete_non_isoc_xfer_ddma()

Fixes a static analysis issue in dwc2_complete_non_isoc_xfer_ddma(). The
qtd was being passed to a function after being freed. It was not being
used in the function so this doesn't fix any bugs. But it fixes up the
warning and makes the code safer by setting qtd to NULL and not using it
at all.

Change-Id: I5224d5b7854c23cc0d0931b5a131f93b9a2ce8c8
Reported-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Huang, Tao <huangtao@rock-chips.com>
(cherry picked from commit 1fc659894994c7faa67e51a4b5a981ab4cf0f3a5)