layerscape: add LX2160ARDB (Rev2.0 silicon) board support

layerscape: add LX2160ARDB (Rev2.0 silicon) board support

The QorIQ LX2160A reference design board provides a comprehensive platform
that enables design and evaluation of the LX2160A processor.

- Enables network intelligence with the next generation Datapath (DPPA2)
  which provides differentiated offload and a rich set of IO, including
  10GE, 25GE, 40GE, and PCIe Gen4

- Delivers unprecedented efficiency and new virtualized networks

- Supports designs in 5G packet processing, network function
  virtualization, storage controller, white box switching, network
  interface cards, and mobile edge computing

- Supports all three LX2 family members (16-core LX2160A; 12-core LX2120A;
  and 8-core LX2080A)

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
[use AUTORELEASE, add dtb to firmware part]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>