[media] cx231xx: Use wake_up_interruptible() instead of wake_up_interruptible_nr()

While looking at use cases of the wake queues in order to add support
for simple wait queues, I noticed that there was only a single user of
wake_up_interruptible_nr(), and that use was doing a single task wake
up. Have that user use the proper wake_up_interruptible() instead, and
perhaps we can even remove the function wake_up_interruptible_nr().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>