sh: sh4a scif pdata (sh7343/sh7366/sh7722/sh7723/sh7724)

This patch breaks out the sh4a 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.

Only sh4a SuperH Mobile processors are modified by this
patch.

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