ALSA: fireworks: Fix wrong value as argument for PTR_ERR()

The return value of memdup_user() should be passed to return correct error.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/fireworks/fireworks_hwdep.c

@@ -135,7 +135,7 @@ hwdep_write(struct snd_hwdep *hwdep, const char __user *data, long count,
 
 	buf = memdup_user(data, count);
 	if (IS_ERR(buf))
-		return PTR_ERR(data);
+		return PTR_ERR(buf);
 
 	/* check seqnum is not for kernel-land */
 	seqnum = be32_to_cpu(((struct snd_efw_transaction *)buf)->seqnum);