ALSA: seq: Fix missing channel at encoding RPN/NRPN MIDI2 messages

The conversion from the legacy event to MIDI2 UMP for RPN and NRPN
missed the setup of the channel number, resulting in always the
channel 0.  Fix it.

Fixes: e9e02819 ("ALSA: seq: Automatic conversion of UMP events")
Link: https://patch.msgid.link/20240625095200.25745-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/seq/seq_ump_convert.c

@@ -791,7 +791,8 @@ static int paf_ev_to_ump_midi2(const struct snd_seq_event *event,
 
 /* set up the MIDI2 RPN/NRPN packet data from the parsed info */
 static void fill_rpn(struct snd_seq_ump_midi2_bank *cc,
-		     union snd_ump_midi2_msg *data)
+		     union snd_ump_midi2_msg *data,
+		     unsigned char channel)
 {
 	if (cc->rpn_set) {
 		data->rpn.status = UMP_MSG_STATUS_RPN;
@@ -808,6 +809,7 @@ static void fill_rpn(struct snd_seq_ump_midi2_bank *cc,
 	}
 	data->rpn.data = upscale_14_to_32bit((cc->cc_data_msb << 7) |
 					     cc->cc_data_lsb);
+	data->rpn.channel = channel;
 	cc->cc_data_msb = cc->cc_data_lsb = 0;
 }
 
@@ -855,7 +857,7 @@ static int cc_ev_to_ump_midi2(const struct snd_seq_event *event,
 		cc->cc_data_lsb = val;
 		if (!(cc->rpn_set || cc->nrpn_set))
 			return 0; // skip
-		fill_rpn(cc, data);
+		fill_rpn(cc, data, channel);
 		return 1;
 	}
 
@@ -957,7 +959,7 @@ static int ctrl14_ev_to_ump_midi2(const struct snd_seq_event *event,
 		cc->cc_data_lsb = lsb;
 		if (!(cc->rpn_set || cc->nrpn_set))
 			return 0; // skip
-		fill_rpn(cc, data);
+		fill_rpn(cc, data, channel);
 		return 1;
 	}