dmaengine: constify of_device_id array

of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/mmp_tdma.c

@@ -594,7 +594,7 @@ struct dma_chan *mmp_tdma_xlate(struct of_phandle_args *dma_spec,
 	return dma_request_channel(mask, mmp_tdma_filter_fn, &param);
 }
 
-static struct of_device_id mmp_tdma_dt_ids[] = {
+static const struct of_device_id mmp_tdma_dt_ids[] = {
 	{ .compatible = "marvell,adma-1.0", .data = (void *)MMP_AUD_TDMA},
 	{ .compatible = "marvell,pxa910-squ", .data = (void *)PXA910_SQU},
 	{}