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/ICompactFlashLockUnlockPatchCode.h

@@ -0,0 +1,13 @@
+#pragma once
+
+/// @brief Interface for patch code implementing Compact Flash carts lock/unlock routines
+class ICompactFlashLockUnlockPatchCode
+{
+protected:
+    ICompactFlashLockUnlockPatchCode() { }
+
+public:
+    /// @brief Gets a pointer to the SD write function in the patch code.
+    /// @return The pointer to the SD write function.
+    virtual const void* GetLockUnlockFunction() const = 0;
+};