ALSA: fireworks: fix an endianness bug for transaction length

commit 92cb4658 upstream.

Although the 't->length' is a big-endian value, it's used without any
conversion. This means that the driver always uses 'length' parameter.

Fixes: 555e8a8f("ALSA: fireworks: Add command/response functionality into hwdep interface")
Reported-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

sound/firewire/fireworks/fireworks_transaction.c

@@ -124,7 +124,7 @@ copy_resp_to_buf(struct snd_efw *efw, void *data, size_t length, int *rcode)
 	spin_lock_irq(&efw->lock);
 
 	t = (struct snd_efw_transaction *)data;
-	length = min_t(size_t, t->length * sizeof(t->length), length);
+	length = min_t(size_t, be32_to_cpu(t->length) * sizeof(u32), length);
 
 	if (efw->push_ptr < efw->pull_ptr)
 		capacity = (unsigned int)(efw->pull_ptr - efw->push_ptr);