ALSA: info: Drop unused snd_info_entry.card field

It's referred only in snd_card_id_read() which can receive the card
object via private_data.
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/info.h

@@ -82,7 +82,6 @@ struct snd_info_entry {
 		struct snd_info_entry_ops *ops;
 	} c;
 	struct snd_info_entry *parent;
-	struct snd_card *card;
 	struct module *module;
 	void *private_data;
 	void (*private_free)(struct snd_info_entry *entry);

sound/core/info.c

@@ -750,10 +750,8 @@ struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 	if (!parent)
 		parent = card->proc_root;
 	entry = snd_info_create_entry(name, parent);
-	if (entry) {
+	if (entry)
 		entry->module = card->module;
-		entry->card = card;
-	}
 	return entry;
 }
 EXPORT_SYMBOL(snd_info_create_card_entry);

sound/core/init.c

@@ -104,7 +104,9 @@ EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
 static void snd_card_id_read(struct snd_info_entry *entry,
 			     struct snd_info_buffer *buffer)
 {
-	snd_iprintf(buffer, "%s\n", entry->card->id);
+	struct snd_card *card = entry->private_data;
+
+	snd_iprintf(buffer, "%s\n", card->id);
 }
 
 static int init_info_for_card(struct snd_card *card)
@@ -116,7 +118,7 @@ static int init_info_for_card(struct snd_card *card)
 		dev_dbg(card->dev, "unable to create card entry\n");
 		return -ENOMEM;
 	}
-	entry->c.text.read = snd_card_id_read;
+	snd_info_set_text_ops(entry, card, snd_card_id_read);
 	card->proc_id = entry;
 
 	return snd_info_card_register(card);