usb: musb: fix device hotplug behind hub

The commit 889ad3b "usb: musb: try a race-free wakeup" breaks device
hotplug enumeraitonn when the device is connected behind a hub while usb
autosuspend is enabled.

Adding finish_resume_work into runtime resume callback fixes the issue.

Also resume root hub is required to resume the bus from runtime suspend,
so move musb_host_resume_root_hub() back to its original location, where
handles RESUME interrupt.
Signed-off-by: Bin Liu <b-liu@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/musb_core.c

@@ -567,6 +567,7 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 
 				musb->xceiv->otg->state = OTG_STATE_A_HOST;
 				musb->is_active = 1;
+				musb_host_resume_root_hub(musb);
 				break;
 			case OTG_STATE_B_WAIT_ACON:
 				musb->xceiv->otg->state = OTG_STATE_B_PERIPHERAL;
@@ -2500,6 +2501,12 @@ static int musb_runtime_resume(struct device *dev)
 		musb_restore_context(musb);
 	first = 0;
 
+	if (musb->need_finish_resume) {
+		musb->need_finish_resume = 0;
+		schedule_delayed_work(&musb->finish_resume_work,
+				msecs_to_jiffies(20));
+	}
+
 	return 0;
 }
 

drivers/usb/musb/musb_virthub.c

@@ -72,7 +72,6 @@ void musb_host_finish_resume(struct work_struct *work)
 	musb->xceiv->otg->state = OTG_STATE_A_HOST;
 
 	spin_unlock_irqrestore(&musb->lock, flags);
-	musb_host_resume_root_hub(musb);
 }
 
 void musb_port_suspend(struct musb *musb, bool do_suspend)