TTY: bfin_jtag_comm, add tty_port

And use open count from there. Switch to tty from there will follow.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: uclinux-dist-devel@blackfin.uclinux.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>