dmaengine: mv_xor: Remove device_control

The Marvell XOR engine doesn't allow any operations that use to be defined in
device_control, it shouldn't need to be defined. Since it's going to be
deprecated, remove it altogether.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>