sound: Remove unnecessary casts of private_data

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/isa/azt2320.c b/sound/isa/azt2320.c
index f7aa637..aac8dc1 100644
--- a/sound/isa/azt2320.c
+++ b/sound/isa/azt2320.c
@@ -188,7 +188,7 @@
 				sizeof(struct snd_card_azt2320), &card);
 	if (error < 0)
 		return error;
-	acard = (struct snd_card_azt2320 *)card->private_data;
+	acard = card->private_data;
 
 	if ((error = snd_card_azt2320_pnp(dev, acard, pcard, pid))) {
 		snd_card_free(card);