SCI: Fix SCI1late fade complete signal

This fixes duplicate music playing in LauraBow2CD (#6462)

engines/sci/sound/soundcmd.cpp

@@ -508,9 +508,17 @@ void SoundCommandParser::processUpdateCues(reg_t obj) {
 		// fireworks).
 		// It is also needed in other games, e.g. LSL6 when talking to the
 		// receptionist (bug #3192166).
-		// CHECKME: At least kq5cd/win and kq6 set signal to 0xFE here, but
-		// kq5cd/dos does not set signal at all. Needs more investigation.
-		writeSelectorValue(_segMan, obj, SELECTOR(signal), SIGNAL_OFFSET);
+		// TODO: More thorougly check the different SCI version:
+		// * SCI1late sets signal to 0xFE here. (With signal 0xFF
+		//       duplicate music plays in LauraBow2CD - bug #6462)
+		// * Other SCI1 games seem to rely on processStopSound to set the signal
+		// * Need to check SCI0 behaviour.
+		uint16 sig;
+		if (_soundVersion >= SCI_VERSION_1_LATE)
+			sig = 0xFFFE;
+		else
+			sig = SIGNAL_OFFSET;
+		writeSelectorValue(_segMan, obj, SELECTOR(signal), sig);
 		if (_soundVersion <= SCI_VERSION_0_LATE) {
 			processStopSound(obj, false);
 		} else {