V4L/DVB (5178): Avoid race when deregistering the IR control for dvb-usb

V4L/DVB (5178): Avoid race when deregistering the IR control for dvb-usb

The work item function is dvb_usb_read_remote_control():
        INIT_WORK(&d->rc_query_work, dvb_usb_read_remote_control, d);
and the last piece of work it does is:
        schedule_delayed_work(&d->rc_query_work,msecs_to_jiffies(d->props.rc_interval));
Hence you need to call "cancel_rearming_delayed_work()" and not
"cancel_delayed_work()", correct?  I certainly haven't seen this oops
reoccur since I applied this patch.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>