[media] saa7164: poll mask set incorrectly

list_first_entry() always returns non-null here.  I think the intent was
to test whether there were any entries in the used list.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/saa7164/saa7164-encoder.c

@@ -1246,7 +1246,6 @@ static unsigned int fops_poll(struct file *file, poll_table *wait)
 	struct saa7164_encoder_fh *fh =
 		(struct saa7164_encoder_fh *)file->private_data;
 	struct saa7164_port *port = fh->port;
-	struct saa7164_user_buffer *ubuf;
 	unsigned int mask = 0;
 
 	port->last_poll_msecs_diff = port->last_poll_msecs;
@@ -1278,10 +1277,7 @@ static unsigned int fops_poll(struct file *file, poll_table *wait)
 	}
 
 	/* Pull the first buffer from the used list */
-	ubuf = list_first_entry(&port->list_buf_used.list,
-		struct saa7164_user_buffer, list);
-
-	if (ubuf)
+	if (!list_empty(&port->list_buf_used.list))
 		mask |= POLLIN | POLLRDNORM;
 
 	return mask;

drivers/media/video/saa7164/saa7164-vbi.c

@@ -1192,7 +1192,6 @@ static unsigned int fops_poll(struct file *file, poll_table *wait)
 {
 	struct saa7164_vbi_fh *fh = (struct saa7164_vbi_fh *)file->private_data;
 	struct saa7164_port *port = fh->port;
-	struct saa7164_user_buffer *ubuf;
 	unsigned int mask = 0;
 
 	port->last_poll_msecs_diff = port->last_poll_msecs;
@@ -1224,10 +1223,7 @@ static unsigned int fops_poll(struct file *file, poll_table *wait)
 	}
 
 	/* Pull the first buffer from the used list */
-	ubuf = list_first_entry(&port->list_buf_used.list,
-		struct saa7164_user_buffer, list);
-
-	if (ubuf)
+	if (!list_empty(&port->list_buf_used.list))
 		mask |= POLLIN | POLLRDNORM;
 
 	return mask;