Ensure that anything opened with openat is tracked in our FD map

Missing this was an accident, this was how it was supposed to be.
It's very helpful to map FDs to filenames when tracking mmap mappings

External/FEXCore/Source/Interface/HLE/FileManagement.cpp

@@ -140,11 +140,11 @@ uint64_t FileManager::Openat([[maybe_unused]] int dirfs, const char *pathname, i
 
     if (fd == -1)
       fd = ::openat(dirfs, pathname, flags, mode);
-
-    return fd;
   }
 
-  FDToNameMap[fd] = pathname;
+  if (fd != -1)
+    FDToNameMap[fd] = pathname;
+
   return fd;
 }