dmaengine: imx-sdma: convert callback to helper function

This is in preperation of moving to a callback that provides results to the
callback for the transaction. The conversion will maintain current behavior
and the driver must convert to new callback mechanism at a later time in
order to receive results.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 03ec76f..624facb 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -650,8 +650,7 @@
 
 static void sdma_handle_channel_loop(struct sdma_channel *sdmac)
 {
-	if (sdmac->desc.callback)
-		sdmac->desc.callback(sdmac->desc.callback_param);
+	dmaengine_desc_get_callback_invoke(&sdmac->desc, NULL);
 }
 
 static void sdma_update_channel_loop(struct sdma_channel *sdmac)
@@ -701,8 +700,8 @@
 		sdmac->status = DMA_COMPLETE;
 
 	dma_cookie_complete(&sdmac->desc);
-	if (sdmac->desc.callback)
-		sdmac->desc.callback(sdmac->desc.callback_param);
+
+	dmaengine_desc_get_callback_invoke(&sdmac->desc, NULL);
 }
 
 static void sdma_tasklet(unsigned long data)