usb: dwc3: Clear TRBs after removing requests

There is a race between START_XFER and END_XFER where
START_XFER happened from ep_queue(function driver) even
after giving back the requests with -ESHUTDOWN because of reset.
Since the HWO bit is set for the TRBs even after stop active
transfers is completed successfully there is a possiblity that
controller can still go ahead and access the TRB which can lead
to SMMU fault.

Clearing TRBs after removing requests ensures that HWO
bit of all the TRBs are cleared and controller will
not access any TRB after stop active transfers is completed.

Change-Id: If047c462a68572eb948fb96182985a876ad80c35
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>