staging: fsl-dpaa2/eth: Add Freescale DPAA2 Ethernet driver

Introduce the DPAA2 Ethernet driver, which manages Datapath
Network Interface (DPNI) objects discovered on the MC bus.

In addition to DPNIs, the Ethernet driver uses several other
MC objects to build a network interface abstraction: buffer
pools (DPBPs), I/O Portals (DPIOs) and concentrators (DPCONs).

A more detailed description of the driver can be found in the
associated README file.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Bogdan Hamciuc <bogdan.hamciuc@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>