85xx: Add support for P2020RDB board

The code base adds P1 & P2 RDB platforms support.
The folder and file names can cater to future SOCs of P1/P2 family.
P1 & P2 processors are 85xx platforms, part of Freescale QorIQ series.

Tested following on P2020RDB:
1. eTSECs
2. DDR, NAND, NOR, I2C.

Signed-off-by: Poonam Aggrwal <poonam.aggrwal@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>