dmaengine: sh: fix some NULL dereferences

The dma_free_coherent() function needs a valid device pointer or it will
crash.

Fixes: 550c591 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20210827085410.GA9183@kili
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: Dan Carpenter

drivers/dma/sh/rz-dmac.c

@@ -919,7 +919,7 @@ static int rz_dmac_probe(struct platform_device *pdev)
 	for (i = 0; i < channel_num; i++) {
 		struct rz_dmac_chan *channel = &dmac->channels[i];
 
-		dma_free_coherent(NULL,
+		dma_free_coherent(&pdev->dev,
 				  sizeof(struct rz_lmdesc) * DMAC_NR_LMDESC,
 				  channel->lmdesc.base,
 				  channel->lmdesc.base_dma);
@@ -936,7 +936,7 @@ static int rz_dmac_remove(struct platform_device *pdev)
 	for (i = 0; i < dmac->n_channels; i++) {
 		struct rz_dmac_chan *channel = &dmac->channels[i];
 
-		dma_free_coherent(NULL,
+		dma_free_coherent(&pdev->dev,
 				  sizeof(struct rz_lmdesc) * DMAC_NR_LMDESC,
 				  channel->lmdesc.base,
 				  channel->lmdesc.base_dma);