TTY: mxser+cyclades remove wait_until_sent debug code

It makes the code really ugly. And since it can be enabled only before
building and only in the source files, it can be barely used by users.
That said, I've not seen anybody to use it in the past few years.

This crap is copied to some more drivers over the tty tree. Since I'm
not their maintainer, I'm not sure if I should remove them too?

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>