This serial port is used on all 8xx, many 82xx, and some 85xx chips.

The driver requires that the port has already been set up by the firmware
and/or platform code.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>