I've never followed these instructions, however...
Looking at it, wget should create a file in your current working directory called tbs6981.config. You can then copy it to ./v4l/.config with "cp tbs6981.config ./v4l/.config". That will create afile called ".config", not a directory - and this file won't show up on a normal ls command.
Try these two after issuing the copy command:
ls ./v4l
ls -la ./v4l
... and you should find that you can see the .config file in the second example, but not the first.
Alternatively, if a
directory called ./v4l/.config already exists, then there will be a file create in that directory called tbs6981.config when you issue the cp command. Again, the .config folder wouldn't show on an ls command, but will on an ls -la.