Add support for Slot 2 flashcarts using Compact Flash (#84)

- Supercard CF (SUPERCARDCF)
- GBA Media Player CF (MPCF)
- M3 Adapter CF (M3CF)
- Max Media Dock CF (MMCF)

arm9/source/patches/platform/compactflash-common/CompactFlashRegisters.h

@@ -0,0 +1,15 @@
+#pragma once
+#include "common.h"
+
+struct cf_registers_t
+{
+    vu16* data;
+    vu16* altStatus;
+    vu16* command;
+    vu16* error;
+    vu16* sectorCount;
+    vu16* lba1;
+    vu16* lba2;
+    vu16* lba3;
+    vu16* lba4;
+};