ALSA: ctl: confirm to return all identical information in 'activate' event

When event originator doesn't set numerical ID in identical information,
the event data includes no numerical ID, thus userspace applications
cannot identify the control just by unique ID in event data.

This commit fix this bug so as the event data includes all of identical
information.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/control.c

@@ -578,6 +578,7 @@ error:
  *
  * Finds the control instance with the given id, and activate or
  * inactivate the control together with notification, if changed.
+ * The given ID data is filled with full information.
  *
  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
  */
@@ -607,6 +608,7 @@ int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 			goto unlock;
 		vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 	}
+	snd_ctl_build_ioff(id, kctl, index_offset);
 	ret = 1;
  unlock:
 	up_write(&card->controls_rwsem);