IMX/DMA : set the DMA direction in the sdma_control()

Set the right DMA direction in the sdma_control(), else
we will get the wrong log when enable the DYNAMIC_DEBUG.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>