powerpc/85xx: add P1020RDB-PD platform support

The p1020rdb-pd has the similar feature as the p1020rdb.
Therefore, p1020rdb-pd use the same platform file as the p1/p2 rdb board.
Overview of P1020RDB-PD platform:
- DDR3 2GB
- NOR flash 64MB
- NAND flash 128MB
- SPI flash 16MB
- I2C EEPROM 256Kb
	- eTSEC1 (RGMII PHY) connected to VSC7385 L2 switch
	- eTSEC2 (SGMII PHY)
- eTSEC3 (RGMII PHY)
	- SDHC
	- 2 USB ports
	- 4 TDM ports
	- PCIe

Signed-off-by: Haijun Zhang <Haijun.Zhang@freescale.com>
Signed-off-by: Jerry Huang <Chang-Ming.Huang@freescale.com>
CC: Scott Wood <scottwood@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>