usb: dwc3: Issue ENDTRANSFER cmd on ep0 unconditionally

Consider a case where ep0 is not in setup stage and composition
switch happens. Currently DWC3_DEPCMD_ENDTRANSFER command is not
issued on ep0 which means that the transfers are not flushed out
and driver clears the run/stop bit hence stopping the controller.
Now as soon as driver sets the run/stop bit controller tries to
access the trb from the previous session which is already unmapped
resulting in SMMU fault.

Fix this by unconditionally issuing DWC3_DEPCMD_ENDTRANSFER
command on ep0. Although it is not specified in the data book
but if we know for sure that we are anyway going to stop the
controller then we can issue ENDTRANSFER command on ep0.

Change-Id: Ic6ee570acc8926897d3b6042181a501a47438d92
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>