ALSA: cmi8330: fix MPU-401 PnP init copy&paste bug

Fix copy&paste bug in PnP MPU-401 initialization.
Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/isa/cmi8330.c

@@ -338,7 +338,7 @@ static int __devinit snd_cmi8330_pnp(int dev, struct snd_cmi8330 *acard,
 		return -EBUSY;
 
 	acard->mpu = pnp_request_card_device(card, id->devs[2].id, NULL);
-	if (acard->play == NULL)
+	if (acard->mpu == NULL)
 		return -EBUSY;
 
 	pdev = acard->cap;