ALSA: fireworks: fix wrong return count shorter than expected by 4 bytes

commit eb9d84b upstream.

ALSA fireworks driver has a bug in its initial state to return count
shorter than expected by 4 bytes to userspace applications when handling
response frame for Echo Audio Fireworks transaction. It's due to missing
addition of the size for the type of event in ALSA firewire stack.

Fixes: 555e8a8 ("ALSA: fireworks: Add command/response functionality into hwdep interface")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20220424102428.21109-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sound/firewire/fireworks/fireworks_hwdep.c

@@ -34,6 +34,7 @@ hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained,
 	type = SNDRV_FIREWIRE_EVENT_EFW_RESPONSE;
 	if (copy_to_user(buf, &type, sizeof(type)))
 		return -EFAULT;
+	count += sizeof(type);
 	remained -= sizeof(type);
 	buf += sizeof(type);