fix Neo Geo detuning

src/engine/engine.cpp

@@ -1545,6 +1545,11 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
     ds.linearPitch=true;
     ds.loopModality=0;
 
+    // Neo Geo detune
+    if (ds.system[0]==DIV_SYSTEM_YM2610 || ds.system[0]==DIV_SYSTEM_YM2610_EXT) {
+      ds.tuning=443.23;
+    }
+
     logI("reading module data...\n");
     if (ds.version>0x0c) {
       ds.hilightA=reader.readC();

src/engine/platform/ym2610shared.h

@@ -26,4 +26,4 @@ static int orderedOps[4]={
 #define rWrite(a,v) if (!skipRegisterWrites) {pendingWrites[a]=v;}
 #define immWrite(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
 
-#define CHIP_FREQBASE 9509775
+#define CHIP_FREQBASE 9440540