GameSettings: Immediate XFB off for MGS Special Disc

Data/Sys/GameSettings/PGS.ini

@@ -12,6 +12,9 @@
 [ActionReplay]
 # Add action replay cheats here.
 
+[Video_Hacks]
+ImmediateXFBEnable = False
+
 [Video_Settings]
 # override value that was set in P.ini back to defaults
-SafeTextureCacheColorSamples = 
+SafeTextureCacheColorSamples =