dma: mmp_tdma: move to generic device tree binding

    This patch makes the mmp_tdma controller able to provide DMA
resources in DT environments by providing an dma xlate function to
get the generic DMA device tree helper support. Then DMA clients only
need to call dma_request_slave_channel() for requesting a DMA channel
from dmaengine.

Signed-off-by: Nenghua Cao <nhcao@marvell.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>