dmaengine: mv_xor_v2: new driver

The new mv_xor_v2 driver supports the XOR engines found in the 64-bits
ARM from Marvell of the Armada 7K and Armada 8K family. This XOR
engine is a completely new hardware block, entirely different from the
one used on previous Marvell Armada platforms, which use the existing
mv_xor driver.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>