ALSA: ump: Shut up truncated string warning

The recent change for the legacy substream name update brought a
compile warning for some compilers due to the nature of snprintf().
Use scnprintf() to shut up the warning since the truncation is
intentional.

Fixes: e29e504 ("ALSA: ump: Indicate the inactive group in legacy substream names")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202411300103.FrGuTAYp-lkp@intel.com/
Link: https://patch.msgid.link/20241130090009.19849-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/ump.c

@@ -1262,9 +1262,9 @@ static void fill_substream_names(struct snd_ump_endpoint *ump,
 		name = ump->groups[idx].name;
 		if (!*name)
 			name = ump->info.name;
-		snprintf(s->name, sizeof(s->name), "Group %d (%.16s)%s",
-			 idx + 1, name,
-			 ump->groups[idx].active ? "" : " [Inactive]");
+		scnprintf(s->name, sizeof(s->name), "Group %d (%.16s)%s",
+			  idx + 1, name,
+			  ump->groups[idx].active ? "" : " [Inactive]");
 	}
 }