Boot: Add support for booting NAND titles with just the ID

Source/Core/Core/Boot/Boot.h

@@ -50,6 +50,11 @@ struct BootParameters
     std::string content_path;
   };
 
+  struct NANDTitle
+  {
+    u64 id;
+  };
+
   struct IPL
   {
     explicit IPL(DiscIO::Region region_);
@@ -67,7 +72,7 @@ struct BootParameters
 
   static std::unique_ptr<BootParameters> GenerateFromFile(const std::string& path);
 
-  using Parameters = std::variant<Disc, Executable, NAND, IPL, DFF>;
+  using Parameters = std::variant<Disc, Executable, NAND, NANDTitle, IPL, DFF>;
   BootParameters(Parameters&& parameters_);
 
   Parameters parameters;
@@ -99,6 +104,7 @@ private:
   static void UpdateDebugger_MapLoaded();
 
   static bool Boot_WiiWAD(const std::string& filename);
+  static bool BootNANDTitle(u64 title_id);
 
   static void SetupMSR();
   static void SetupBAT(bool is_wii);
@@ -109,7 +115,7 @@ private:
   static bool Load_BS2(const std::string& boot_rom_filename);
 
   static void SetupGCMemory();
-  static bool SetupWiiMemory(u64 ios_title_id);
+  static bool SetupWiiMemory();
 };
 
 class BootExecutableReader