[VFS] Make ResolvePath argument a const reference.

src/xenia/vfs/devices/host_path_device.cc

@@ -48,7 +48,7 @@ void HostPathDevice::Dump(StringBuffer* string_buffer) {
   root_entry_->Dump(string_buffer, 0);
 }
 
-Entry* HostPathDevice::ResolvePath(std::string path) {
+Entry* HostPathDevice::ResolvePath(const std::string& path) {
   // The filesystem will have stripped our prefix off already, so the path will
   // be in the form:
   // some\PATH.foo