Miscellaneous DSi NAND fixes (#1852)

* Replace some standard I/O calls with Platform equivalents

- I missed a spot when I submitted that PR a few months ago

* Include <memory> in DSi_NAND.h

- Because it uses unique_ptr

* Split DSi_NAND::ReadHardwareInfo into ReadSerialData and ReadHardwareInfoN

* Add a RegionMask enum

* Move DSi NAND patching to the frontend

* Add DSiSupportedLanguageMask

- Not currently used by the frontend, but I use it in melonDS DS

* Remove some Platform::ConfigEntry values

- The core no longer needs to know about them
- The corresponding Config values are unchanged

* Mark NANDMount's destructor as noexcept

src/NDSCart.cpp

@@ -1650,8 +1650,7 @@ std::unique_ptr<CartCommon> ParseROM(const u8* romdata, u32 romlen)
     bool dsi = header.IsDSi();
     bool badDSiDump = false;
 
-    u32 dsiRegion = header.DSiRegionMask;
-    if (dsi && dsiRegion == 0)
+    if (dsi && header.DSiRegionMask == RegionMask::NoRegion)
     {
         Log(LogLevel::Info, "DS header indicates DSi, but region is zero. Going in bad dump mode.\n");
         badDSiDump = true;