usb: dwc3: gadget: Only End Transfer for ep0 data phase

The driver shouldn't be able to issue End Transfer to the control
endpoint at anytime. Typically we should only do so in error cases such
as invalid/unexpected direction of Data Phase as described in the
control transfer flow of the programming guide. It _may_ end started
data phase during controller deinitialization from soft disconnect or
driver removal. However, that should not happen because the driver
should be maintained in EP0_SETUP_PHASE during driver tear-down. On
soft-connect, the controller should be reset from a soft-reset and there
should be no issue starting the control endpoint.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/3c6643678863a26702e4115e9e19d7d94a30d49c.1650593829.git.Thinh.Nguyen@synopsys.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>