ALSA: firewire-digi00x: prevent potential use after free

This code was supposed to return an error code if init_stream()
failed, but it instead freed dg00x->rx_stream and returned success.
This potentially leads to a use after free.

Fixes: 9a08067 ("ALSA: firewire-digi00x: support AMDTP domain")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/c224cbd5-d9e2-4cd4-9bcf-2138eb1d35c6@kili.mountain
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Author: Dan Carpenter

sound/firewire/digi00x/digi00x-stream.c

@@ -259,8 +259,10 @@ int snd_dg00x_stream_init_duplex(struct snd_dg00x *dg00x)
 		return err;
 
 	err = init_stream(dg00x, &dg00x->tx_stream);
-	if (err < 0)
+	if (err < 0) {
 		destroy_stream(dg00x, &dg00x->rx_stream);
+		return err;
+	}
 
 	err = amdtp_domain_init(&dg00x->domain);
 	if (err < 0) {