ALSA: bebob: enable to deliver MIDI messages for multiple ports

Current implementation of bebob driver doesn't correctly handle the case
that the device has multiple MIDI ports. The cause is the number of MIDI
conformant data channels is passed to AM824 data block processing layer.

This commit fixes the bug.
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210321032831.340278-4-o-takashi@sakamocchi.jpSigned-off-by: NTakashi Iwai <tiwai@suse.de>

sound/firewire/bebob/bebob_stream.c

@@ -517,20 +517,22 @@ int snd_bebob_stream_init_duplex(struct snd_bebob *bebob)
 static int keep_resources(struct snd_bebob *bebob, struct amdtp_stream *stream,
 			  unsigned int rate, unsigned int index)
 {
-	struct snd_bebob_stream_formation *formation;
+	unsigned int pcm_channels;
+	unsigned int midi_ports;
 	struct cmp_connection *conn;
 	int err;
 
 	if (stream == &bebob->tx_stream) {
-		formation = bebob->tx_stream_formations + index;
+		pcm_channels = bebob->tx_stream_formations[index].pcm;
+		midi_ports = bebob->midi_input_ports;
 		conn = &bebob->out_conn;
 	} else {
-		formation = bebob->rx_stream_formations + index;
+		pcm_channels = bebob->rx_stream_formations[index].pcm;
+		midi_ports = bebob->midi_output_ports;
 		conn = &bebob->in_conn;
 	}
 
-	err = amdtp_am824_set_parameters(stream, rate, formation->pcm,
-					 formation->midi, false);
+	err = amdtp_am824_set_parameters(stream, rate, pcm_channels, midi_ports, false);
 	if (err < 0)
 		return err;