linux-phytec-fsl

dmaengine: imx: Constify platform_device_id

The platform_device_id is not modified by the driver and core uses it as
const.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>