usb: dwc3: remove unused @lock member of dwc3_ep struct

The member @lock of dwc3_ep struct is only initialized,
and not used elsewhere, so remove it.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/gadget.c

@@ -2271,8 +2271,6 @@ static int dwc3_gadget_init_endpoint(struct dwc3 *dwc, u8 epnum)
 		dep->endpoint.comp_desc = NULL;
 	}
 
-	spin_lock_init(&dep->lock);
-
 	if (num == 0)
 		ret = dwc3_gadget_init_control_endpoint(dep);
 	else if (direction)