[media] media-device: Fix a comment

The comment is for the wrong function. Fix it.
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

include/media/media-device.h

@@ -494,7 +494,7 @@ int __must_check __media_device_register(struct media_device *mdev,
 #define media_device_register(mdev) __media_device_register(mdev, THIS_MODULE)
 
 /**
- * __media_device_unregister() - Unegisters a media device element
+ * media_device_unregister() - Unregisters a media device element
  *
  * @mdev:	pointer to struct &media_device
  *