This patch adds a driver for the DMA controller found in the Ingenic
JZ4780.

It currently does not implement any support for the programmable firmware
feature of the controller - this is not necessary for most uses. It also
does not take priority into account when allocating channels, it just
allocates the first available channel. This can be implemented later.
Signed-off-by: NAlex Smith <alex.smith@imgtec.com>
Signed-off-by: NZubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
[Updated for dmaengine api changes, Add residue support, couple of minor fixes]
Signed-off-by: NVinod Koul <vinod.koul@intel.com>