Lets fix Stuart Little 2 properly (maybe?)

This game cart may have a flashcontroller but no flashram onboard, the game automatically goes down the Flash Type path and hits a stackoverflow at cpuSaveGameFunc after cpuSramEnabled returns as false

I'm not sure of the specifics, but with this change it seems to avoid this condition.

I have tested a number of titles that create Sram, 512 and 1024Mbit flash and they all still seem to just fine.

src/gba/Flash.cpp

@@ -103,6 +103,9 @@ void flashSaveDecide(uint32_t address, uint8_t byte)
             cpuSramEnabled ? "SRAM" : "FLASH", address, byte);
     }
 
+    if (coreOptions.saveType == GBA_SAVE_NONE)
+        return;
+
     (*cpuSaveGameFunc)(address, byte);
 }