usb: dwc3: ep0: remove second giveback in error case

We already give requests back in dwc3_ep0_stall_and_restart() so
doing it again here will most likely corrupt the list.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>