ALSA: hda_audio_ext: fix kernel-doc

Add missing @
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20210812225904.171529-3-pierre-louis.bossart@linux.intel.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/hdaudio_ext.h

@@ -51,7 +51,7 @@ enum hdac_ext_stream_type {
  * @decoupled: stream host and link is decoupled
  * @link_locked: link is locked
  * @link_prepared: link is prepared
- * link_substream: link substream
+ * @link_substream: link substream
  */
 struct hdac_ext_stream {
 	struct hdac_stream hstream;