Revert "USB: quatech2: only write to the tty if the port is open."

This reverts commit 27b351c5.  It caused
problems with the build.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Bill Pemberton <wfp5p@viridian.itc.virginia.edu>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>