Fix NOSOUND build

Follow-up to 9d082389d8

Source/sound_stubs.cpp

@@ -20,12 +20,13 @@ TSnd::~TSnd()
 void snd_init() { }
 void snd_deinit() { }
 void music_stop() { }
-void music_start(uint8_t nTrack) { }
+void music_start(_music_id nTrack) { }
 void sound_disable_music(bool disable) { }
 int sound_get_or_set_music_volume(int volume) { return 0; }
 int sound_get_or_set_sound_volume(int volume) { return 0; }
 void music_mute() { }
 void music_unmute() { }
+_music_id GetLevelMusic(dungeon_type dungeonType) { return TMUSIC_TOWN; }
 // clang-format on
 
 } // namespace devilution