drivers/usb/serial/mos7720.c: inconsequent NULL checking

[Adrian Bunk <bunk@stusta.de>]

The Coverity checker noted the following inconsequent NULL checking in 
drivers/usb/serial/mos7720.c:

<--  snip  -->

...
static void mos7720_close(struct usb_serial_port *port, struct file *filp)
{
...

        /* While closing port, shutdown all bulk read, write  *
         * and interrupt read if they exists                  */
        if (serial->dev) {
                dbg("Shutdown bulk write");
                usb_kill_urb(port->write_urb);
                dbg("Shutdown bulk read");
                usb_kill_urb(port->read_urb);
        }

        data = 0x00;
        send_mos_cmd(serial, MOS_WRITE, port->number - port->serial->minor,
                     0x04, &data);
...

<--  snip  -->

Note that "send_mos_cmd(serial,...)" dereferences "serial->dev".

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed