powerpc/85xx: Add P1023RDB board support

powerpc/85xx: Add P1023RDB board support

P1023RDB Specification:
-----------------------
Memory subsystem:
   512MB DDR3 (Fixed DDR on board)
   64MB NOR flash
   128MB NAND flash

Ethernet:
   eTSEC1: Connected to Atheros AR8035 GETH PHY
   eTSEC2: Connected to Atheros AR8035 GETH PHY

PCIe:
   Three mini-PCIe slots

USB:
   Two USB2.0 Type A ports

I2C:
   AT24C08 8K Board EEPROM (8 bit address)

Signed-off-by: Chunhe Lan <Chunhe.Lan@freescale.com>
Cc: Scott Wood <scottwood@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>