Removing utilities (that were just adding needless layers).

Progress on #294.

src/xenia/vfs/entry.cc

@@ -23,7 +23,7 @@ MemoryMapping::~MemoryMapping() {}
 Entry::Entry(Device* device, const std::string& path)
     : device_(device), path_(path) {
   assert_not_null(device);
-  absolute_path_ = device->path() + path;
+  absolute_path_ = xe::join_paths(device->mount_path(), path);
   name_ = xe::find_name_from_path(path);
 }