usb: dwc2: Drop unlock/lock upon queueing a work item

The original dwc_otg driver used a DWC_WORKQ_SCHEDULE() wrapper to queue
work items.  Because that wrapper acquired the driver's global spinlock,
an unlock/lock dance was necessary whenever a work item was queued up
while the global spinlock was already held.

The dwc2 driver dropped DWC_WORKQ_SCHEDULE() in favor of a direct call
to queue_work(), but retained the (now gratuitous) unlock/lock dance in
dwc2_handle_conn_id_status_change_intr().  Drop it.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Minas Harutyunyan <hminas@synopsys.com>
Acked-by: Felipe Balbi <balbi@kernel.org>
Link: https://lore.kernel.org/r/77c07f00a6a9d94323c4a060a3c72817b0703b97.1574244795.git.lukas@wunner.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc2/core_intr.c

@@ -288,14 +288,9 @@ static void dwc2_handle_conn_id_status_change_intr(struct dwc2_hsotg *hsotg)
 
 	/*
 	 * Need to schedule a work, as there are possible DELAY function calls.
-	 * Release lock before scheduling workq as it holds spinlock during
-	 * scheduling.
 	 */
-	if (hsotg->wq_otg) {
-		spin_unlock(&hsotg->lock);
+	if (hsotg->wq_otg)
 		queue_work(hsotg->wq_otg, &hsotg->wf_otg);
-		spin_lock(&hsotg->lock);
-	}
 }
 
 /**