media/radio/radio-si470x.c: check-after-use

[Adrian Bunk <bunk@kernel.org>]

The Coverity checker spotted the following check-after-use in 
drivers/media/radio/radio-si470x.c:

<--  snip  -->

...
static void si470x_usb_driver_disconnect(struct usb_interface *intf)
{
        struct si470x_device *radio = usb_get_intfdata(intf);

        del_timer_sync(&radio->timer);    <------------------
        flush_scheduled_work();

        usb_set_intfdata(intf, NULL);
        if (radio) {                      <------------------
                video_unregister_device(radio->videodev);
                kfree(radio->buffer);
                kfree(radio);
        }
}
...

<--  snip  -->

Either "radio" can be NULL and this case has to be properly handled or 
the NULL check is not required.

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