ump: Add helpers to parse / set UMP packet data

This patch defines the structs / unions that can be used for encoding
and decoding UMP packets, as well as inline helper functions.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

src/rawmidi/ump_local.h

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 #include "rawmidi.h"
 #include "ump.h"
+#include "ump_msg.h"
 
 struct _snd_ump {
 	snd_rawmidi_t *rawmidi;