serial: omap: add the functionality of a 9-bit UART with userspaces CMSPAR

Some systems require the additional communication functionality of a
9-bit UART. For that we could use the "stick" (mark/space) parity
bit supported on omap serial device. When is set, if PARODD is set the
parity bit is always 1; if PARODD is not set, then the parity bit is
always 0.

Signed-off-by: Enric Balletbo i Serra <eballetbo@iseebcn.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>