sh: sh3 scif pdata (sh7705/sh770x/sh7710/sh7720)

This patch breaks out the sh3 scif serial port platform
data from a shared platform device to one platform
device per port. Also, add serial ports to the list of
early platform devices.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>