TTY: speakup, do not use serialP

The structures there are going away. And speakup has enough troubles
already.

So define a structure similar to what 8250 does: old_serial_port.
There define an array of speed, port base and so on needed for
configuration. Then use this structure instead of serial_state defined
in serialP.h.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: William Hubbs <w.d.hubbs@gmail.com>
Cc: Chris Brannon <chris@the-brannons.com>
Cc: Kirk Reiser <kirk@braille.uwo.ca>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>