dvb: Convert "mutex" to semaphore

The usage of this "mutex" is non obvious and probably a completions in
some places. Make it a semaphore.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/dvb-core/dvb_frontend.c

@@ -678,7 +678,7 @@ static void dvb_frontend_stop(struct dvb_frontend *fe)
 
 	kthread_stop(fepriv->thread);
 
-	init_MUTEX (&fepriv->sem);
+	semaphore_init(&fepriv->sem);
 	fepriv->state = FESTATE_IDLE;
 
 	/* paranoia check in case a signal arrived */
@@ -1909,7 +1909,7 @@ int dvb_register_frontend(struct dvb_adapter* dvb,
 	}
 	fepriv = fe->frontend_priv;
 
-	init_MUTEX (&fepriv->sem);
+	semaphore_init(&fepriv->sem);
 	init_waitqueue_head (&fepriv->wait_queue);
 	init_waitqueue_head (&fepriv->events.wait_queue);
 	mutex_init(&fepriv->events.mtx);