The patch adds support for P2020DS reference platform.
DDR3 interface uses hard-coded initialization rather than SPD
for now and was tested at 667Mhz. Some PIXIS register
definitions and associated code sections need to be fixed.
TSEC1/2/3, NOR flash, MAC/SYS ID EEPROM, PCIE1/2/3 are all
tested under u-boot.