[POWERPC] 8xx: platform related changes to the fsl_soc

Added 8xx SoC peripherials: fec for Ethernet and smc for UARTs.
Ordinary routines to extract values from the device tree and insert
respective platform devices

Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>