dmaengine: mxs-dma: fix unused variable warn

drivers/dma/mxs-dma.c: In function 'mxs_dma_terminate_all':
drivers/dma/mxs-dma.c:662:23: warning: unused variable 'mxs_chan'[-Wunused-variable]
Signed-off-by: NVinod Koul <vinod.koul@intel.com>

drivers/dma/mxs-dma.c

@@ -661,8 +661,6 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_dma_cyclic(
 
 static int mxs_dma_terminate_all(struct dma_chan *chan)
 {
-	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
-
 	mxs_dma_reset_chan(chan);
 	mxs_dma_disable_chan(chan);