Enable the "blitter" for P96 driver

This enables some advanced background functionality for P96, and seems to have no performance drawbacks so far.
It is however possible that this may cause some problems with applications using unusual color formats for their bitmaps.

platforms/amiga/rtg/rtg_driver_amiga/pigfx-2.c

@@ -259,7 +259,7 @@ int __attribute__((used)) InitCard(__REGA0(struct BoardInfo* b)) {
     b->PaletteChipType = PCT_S3ViRGE;
     b->GraphicsControllerType = GCT_S3ViRGE;
 
-    b->Flags |= BIF_GRANTDIRECTACCESS | BIF_HARDWARESPRITE | BIF_FLICKERFIXER;
+    b->Flags |= BIF_GRANTDIRECTACCESS | BIF_HARDWARESPRITE | BIF_FLICKERFIXER | BIF_BLITTER;
     b->RGBFormats = 1 | 2 | 512 | 1024 | 2048;
     b->SoftSpriteFlags = 0;
     b->BitsPerCannon = 8;
@@ -432,9 +432,32 @@ APTR CalculateMemory (__REGA0(struct BoardInfo *b), __REGA1(unsigned long addr),
     return (APTR)addr;
 }
 
+enum fake_rgbftypes {
+    RGBF_8BPP_CLUT,
+    RGBF_24BPP_RGB,
+    RGBF_24BPP_BGR,
+    RGBF_16BPP_RGB565_PC,
+    RGBF_16BPP_RGB555_PC,
+	RGBF_32BPP_ARGB,
+    RGBF_32BPP_ABGR,
+	RGBF_32BPP_RGBA,
+    RGBF_32BPP_BGRA,
+    RGBF_16BPP_RGB565,
+    RGBF_16BPP_RGB555,
+    RGBF_16BPP_BGR565_PC,
+    RGBF_16BPP_BGR555_PC,
+    RGBF_YUV_422_0,  // (Actually 4:2:0?) Just a duplicate of RGBF_YUV_422?
+    RGBF_YUV_411,    // No, these are 4:2:0
+    RGBF_YUV_411_PC, // No, these are 4:2:0
+    RGBF_YUV_422,
+    RGBF_YUV_422_PC,
+    RGBF_YUV_422_PLANAR,
+    RGBF_YUV_422_PLANAR_PC,
+};
+#define BIP(a) (1 << a)
+
 ULONG GetCompatibleFormats (__REGA0(struct BoardInfo *b), __REGD7(RGBFTYPE format)) {
-    // It is of course compatible with all the formats ever.
-    return 0xFFFFFFFF;
+    return BIP(RGBF_8BPP_CLUT) | BIP(RGBF_24BPP_RGB) | BIP(RGBF_24BPP_BGR) | BIP(RGBF_32BPP_ARGB) | BIP(RGBF_32BPP_ABGR) | BIP(RGBF_32BPP_RGBA) | BIP(RGBF_32BPP_BGRA);
 }
 
 //static int display_enabled = 0;