USB: io_ti: clean up termios handling

Don't pass NULL into termios functions when calling them internally
Remove all the crap which then checks for NULL which can't occur now
Clear CMSPAR as it is not supported
Report the baud rate back to the caller properly (See FIXME someone with
the docs)

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>