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/supercardcf/SuperCardCFLockUnlockCardPatchCode.s

@@ -0,0 +1,26 @@
+.cpu arm7tdmi
+.syntax unified
+.thumb
+.section "sccf_lock_unlock", "ax"
+
+.global sccf_lockUnlockCard
+.type sccf_lockUnlockCard, %function
+sccf_lockUnlockCard:
+    cmp r0, #1
+    bne unlock
+@ void sc_change_mode(uint16_t mode);
+sccf_changeMode:
+    push {r1-r3, lr}
+    ldr r2,= 0x09FFFFFE
+    ldr r3,= 0xA55A
+    strh r3, [r2]
+    strh r3, [r2]
+    strh r0, [r2]
+    strh r0, [r2]
+    pop {r1-r3, pc}
+
+unlock:
+    movs r0, #3
+    b sccf_changeMode
+
+.pool