ALSA: oxfw: fix a condition and return code in start_stream()

The amdtp_stream_wait_callback() doesn't return minus value and
the return code is not for error code.

This commit fixes with a propper condition and an error code.

Fixes: f3699e2c ('ALSA: oxfw: Change the way to start stream')
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: <stable@vger.kernel.org> # 3.19+
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/oxfw/oxfw-stream.c

@@ -171,9 +171,10 @@ static int start_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream,
 	}
 
 	/* Wait first packet */
-	err = amdtp_stream_wait_callback(stream, CALLBACK_TIMEOUT);
-	if (err < 0)
+	if (!amdtp_stream_wait_callback(stream, CALLBACK_TIMEOUT)) {
 		stop_stream(oxfw, stream);
+		err = -ETIMEDOUT;
+	}
 end:
 	return err;
 }