usb: Set unused ports to "fixed" rather than "unknown"

The Microsoft document "Using ACPI to Configure USB Ports on a Computer"
makes it clear that the removable flag will be cleared on ports that are
marked as unused by the firmware. Handle this case to match.
Signed-off-by: Matthew Garrett <mjg59@coreos.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hub.c

@@ -2359,8 +2359,11 @@ static void set_usb_port_removable(struct usb_device *udev)
 		udev->removable = USB_DEVICE_REMOVABLE;
 		return;
 	case USB_PORT_CONNECT_TYPE_HARD_WIRED:
+	case USB_PORT_NOT_USED:
 		udev->removable = USB_DEVICE_FIXED;
 		return;
+	default:
+		break;
 	}
 
 	/*