usb: dwc3: gadget: synchronize_irq dwc irq in suspend

[ Upstream commit 01c10880 ]

We see dwc3 endpoint stopped by unwanted irq during
suspend resume test, which is caused dwc3 ep can't be started
with error "No Resource".

Here, add synchronize_irq before suspend to sync the
pending IRQ handlers complete.
Signed-off-by: Bo He <bo.he@intel.com>
Signed-off-by: Yu Wang <yu.y.wang@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/usb/dwc3/gadget.c

@@ -3274,6 +3274,8 @@ int dwc3_gadget_suspend(struct dwc3 *dwc)
 	dwc3_disconnect_gadget(dwc);
 	__dwc3_gadget_stop(dwc);
 
+	synchronize_irq(dwc->irq_gadget);
+
 	return 0;
 }