Disable ICache emulation for some games

Specifically, 'Scooby-Doo! Mystery Mayhem', 'Scooby-Doo! Unmasked', 'Ed, Edd n Eddy: The Mis-Edventures', and the Wii version of 'Happy Feet'.

The JIT cache causes problems with emulated icache invalidation in these games, resulting in areas failing to load.

Source/Core/Core/ConfigManager.cpp

@@ -512,6 +512,7 @@ void SConfig::LoadCoreSettings(IniFile& ini)
   core->Get("LowDCBZHack", &bLowDCBZHack, false);
   core->Get("FPRF", &bFPRF, false);
   core->Get("AccurateNaNs", &bAccurateNaNs, false);
+  core->Get("DisableICache", &bDisableICache, false);
   core->Get("EmulationSpeed", &m_EmulationSpeed, 1.0f);
   core->Get("Overclock", &m_OCFactor, 1.0f);
   core->Get("OverclockEnable", &m_OCEnable, false);
@@ -749,6 +750,7 @@ void SConfig::LoadDefaults()
   bFastmem = true;
   bFPRF = false;
   bAccurateNaNs = false;
+  bDisableICache = false;
   bMMU = false;
   bLowDCBZHack = false;
   iBBDumpPort = -1;