Use shallow copy to return FATX statfs.

DiscImageChef.CommonTypes/Structs/Filesystems.cs

@@ -241,6 +241,8 @@ namespace DiscImageChef.CommonTypes.Structs
         {
             Id = new FileSystemId();
         }
+
+        public FileSystemInfo ShallowCopy() => (FileSystemInfo)MemberwiseClone();
     }
 
     [StructLayout(LayoutKind.Explicit)]

DiscImageChef.Filesystems/FATX/Super.cs

@@ -243,7 +243,7 @@ namespace DiscImageChef.Filesystems.FATX
             stat = null;
             if(!mounted) return Errno.AccessDenied;
 
-            stat = statfs;
+            stat = statfs.ShallowCopy();
 
             return Errno.NoError;
         }