xhci: gracefully handle xhci_irq dead device

commit 948fa135 upstream.

If the xHCI host controller has died (ie, device removed) or suffered
other serious fatal error (STS_FATAL), then xhci_irq should handle this
condition with IRQ_HANDLED instead of -ESHUTDOWN.
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/usb/host/xhci-ring.c

@@ -2675,7 +2675,7 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
 		xhci_halt(xhci);
 hw_died:
 		spin_unlock(&xhci->lock);
-		return -ESHUTDOWN;
+		return IRQ_HANDLED;
 	}
 
 	/*