USB: serial: fix error message on close in generic driver

Resubmitting read urb fails with -EPERM if completion handler runs while
urb is being killed on close. This should not be reported as an error.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 89fac36..e560d1d 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -415,11 +415,13 @@
 			   ((serial->type->read_bulk_callback) ?
 			     serial->type->read_bulk_callback :
 			     usb_serial_generic_read_bulk_callback), port);
+
 	result = usb_submit_urb(urb, mem_flags);
-	if (result)
+	if (result && result != -EPERM) {
 		dev_err(&port->dev,
 			"%s - failed resubmitting read urb, error %d\n",
 							__func__, result);
+	}
 }
 EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);