More elegant way of solving #5839 (d_private in sceIoDread)

We flag filesystems as being FAT32 instead of checking for "ms0:".

Core/FileSystems/VirtualDiscFileSystem.h

@@ -40,6 +40,7 @@ public:
 	int      DevType(u32 handle);
 	bool GetHostPath(const std::string &inpath, std::string &outpath);
 	std::vector<PSPFileInfo> GetDirListing(std::string path);
+	int  Flags() { return 0; }
 
 	// unsupported operations
 	size_t  WriteFile(u32 handle, const u8 *pointer, s64 size);