dmaengine: cppi41: 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>

drivers/dma/cppi41.c

@@ -331,7 +331,7 @@ static irqreturn_t cppi41_irq(int irq, void *data)
 
 			c->residue = pd_trans_len(c->desc->pd6) - len;
 			dma_cookie_complete(&c->txd);
-			c->txd.callback(c->txd.callback_param);
+			dmaengine_desc_get_callback_invoke(&c->txd, NULL);
 		}
 	}
 	return IRQ_HANDLED;