usb: dwc3: gadget: Remove check for bounded driver

The check for bounded gadget driver in dwc3_gadget_start() was to
prevent going through the initialization again without any cleanup. The
recent commit 49d08cfc ("usb: udc: core: Introduce started state")
updated the UDC framework and guarantees this won't happen while the UDC
is started. Also, this check doesn't prevent requesting threaded irq to
the same dev_id, which will mess up the irq freeing logic. Let's remove
it.
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/ccc90f316cf78bb5f7d46d3fd84f4c7f2c3020b1.1612518764.git.Thinh.Nguyen@synopsys.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/gadget.c

@@ -2411,7 +2411,7 @@ static int dwc3_gadget_start(struct usb_gadget *g,
 {
 	struct dwc3		*dwc = gadget_to_dwc(g);
 	unsigned long		flags;
-	int			ret = 0;
+	int			ret;
 	int			irq;
 
 	irq = dwc->irq_gadget;
@@ -2420,29 +2420,14 @@ static int dwc3_gadget_start(struct usb_gadget *g,
 	if (ret) {
 		dev_err(dwc->dev, "failed to request irq #%d --> %d\n",
 				irq, ret);
-		goto err0;
+		return ret;
 	}
 
 	spin_lock_irqsave(&dwc->lock, flags);
-	if (dwc->gadget_driver) {
-		dev_err(dwc->dev, "%s is already bound to %s\n",
-				dwc->gadget->name,
-				dwc->gadget_driver->driver.name);
-		ret = -EBUSY;
-		goto err1;
-	}
-
 	dwc->gadget_driver	= driver;
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
 	return 0;
-
-err1:
-	spin_unlock_irqrestore(&dwc->lock, flags);
-	free_irq(irq, dwc);
-
-err0:
-	return ret;
 }
 
 static void __dwc3_gadget_stop(struct dwc3 *dwc)