media: dvb_frontend: Use wait_event_freezable_timeout() for freezable kthread

A freezable kernel thread can enter frozen state during freezing by
either calling try_to_freeze() or using wait_event_freezable() and its
variants. So for the following snippet of code in a kernel thread loop:
wait_event_interruptible_timeout();
try_to_freeze();

We can change it to a simple wait_event_freezable_timeout() and
then eliminate a function call.

Signed-off-by: Kevin Hao <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/dvb-core/dvb_frontend.c

···
 	set_freezable();
 	while (1) {
 		up(&fepriv->sem);	    /* is locked when we enter the thread... */
-restart:
-		wait_event_interruptible_timeout(fepriv->wait_queue,
-						 dvb_frontend_should_wakeup(fe) ||
-						 kthread_should_stop() ||
-						 freezing(current),
-			fepriv->delay);
+		wait_event_freezable_timeout(fepriv->wait_queue,
+					     dvb_frontend_should_wakeup(fe) ||
+					     kthread_should_stop(),
+					     fepriv->delay);
 
 		if (kthread_should_stop() || dvb_frontend_is_exiting(fe)) {
 			/* got signal or quitting */
···
 			fe->exit = DVB_FE_NORMAL_EXIT;
 			break;
 		}
-
-		if (try_to_freeze())
-			goto restart;
 
 		if (down_interruptible(&fepriv->sem))
 			break;