powerpc/85xx: add the P1020RDB-PD DTS support

Overview of P1020RDB-PD device:
- 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
- 1 USB ports
- TDM ports
- PCIe

Signed-off-by: Haijun Zhang <Haijun.Zhang@freescale.com>
Signed-off-by: Jerry Huang <Chang-Ming.Huang@freescale.com>
Signed-off-by: Xie Xiaobo-R63061 <X.Xie@freescale.com>
CC: Scott Wood <scottwood@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>