TTY: simserial, remove useless comments

Or the obsolete ones like:
   "Let's have a little bit of fun"
I have never had fun with software. For fun, one needs hard-ware.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>