powerpc/85xx: Added dts for P1021RDB-PC board

P1021RDB-PC Overview
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1Gbyte DDR3 (on board DDR)
16Mbyte NOR flash
32Mbyte eSLC NAND Flash
256 Kbit M24256 I2C EEPROM
128 Mbit SPI Flash memory
Real-time clock on I2C bus
SD/MMC connector to interface with the SD memory card
PCIex
    - x1 PCIe slot or x1 PCIe to dual SATA controller
    - x1 mini-PCIe slot
USB 2.0
    - ULPI PHY interface: SMSC USB3300 USB PHY and Genesys Logic’s GL850A
    - Two USB2.0 Type A receptacles
    - One USB2.0 signal to Mini PCIe slot
eTSEC1: Connected to RGMII PHY VSC7385
eTSEC2: Connected to SGMII PHY VSC8221
eTSEC3: Connected to SGMII PHY AR8021
DUART interface: supports two UARTs up to 115200 bps for console display

Signed-off-by: Matthew McClintock <msm@freescale.com>
Signed-off-by: Xu Jiucheng <B37781@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>