Remove incomplete Use NTSC core option

Use NTSC colors option is incomplete due to missing int,hue adjustments. This can be added but there is no smooth way using core options or hotkey to selec ranges 1-256 for fine tuning

Using shaders instead can work better at this with more adjustments possible

src/palette.c

@@ -34,7 +34,7 @@
 #define M_PI 3.14159265358979323846
 #endif
 
-int ntsccol = 0;
+static int ntsccol = 0;
 static int ntsctint = 46 + 10;
 static int ntschue = 72;