Device drivers should use c_[io]speed directly!

Alan Cox wrote this, so Alan: should I just ditch the use of
uart_get_baud_rate() and program the divider directly from
c_[io]speed?

Yes.

The functions are designed to act as helpers for old devices. In fact
we can actually probably abolish tty_termios_baud_rate at this point as
I don't think there is much if anything left which blows up fed a non
Bxxx table entry.

I will have a look at that in fact see what it involves at this point.

Alan