media: dvbdev: fix build warning due to comments

commit 3edfd14bb5 upstream.

Previous commit that introduces reference counter does not add proper
comments, which will lead to warning when building htmldocs. Fix them.

Reported-by: "Stephen Rothwell" <sfr@canb.auug.org.au>
Fixes: 0fc044b2b5 ("media: dvbdev: adopts refcnt to avoid UAF")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/media/dvbdev.h

@@ -126,6 +126,7 @@ struct dvb_adapter {
  * struct dvb_device - represents a DVB device node
  *
  * @list_head:	List head with all DVB devices
+ * @ref:	reference counter
  * @fops:	pointer to struct file_operations
  * @adapter:	pointer to the adapter that holds this device node
  * @type:	type of the device, as defined by &enum dvb_device_type.
@@ -196,7 +197,7 @@ struct dvb_device {
 struct dvb_device *dvb_device_get(struct dvb_device *dvbdev);
 
 /**
- * dvb_device_get - Decrease dvb_device reference
+ * dvb_device_put - Decrease dvb_device reference
  *
  * @dvbdev:	pointer to struct dvb_device
  */