dmaengine: xgene: devm_ioremap() returns NULL on error

The code here is checking for IS_ERR() but devm_ioremap() returns NULL
on error and not an error pointer.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
index 06d4042..8a36946 100755
--- a/drivers/dma/xgene-dma.c
+++ b/drivers/dma/xgene-dma.c
@@ -1895,9 +1895,9 @@
 
 	pdma->csr_dma = devm_ioremap(&pdev->dev, res->start,
 				     resource_size(res));
-	if (IS_ERR(pdma->csr_dma)) {
+	if (!pdma->csr_dma) {
 		dev_err(&pdev->dev, "Failed to ioremap csr region");
-		return PTR_ERR(pdma->csr_dma);
+		return -ENOMEM;
 	}
 
 	/* Get DMA ring csr region */
@@ -1909,9 +1909,9 @@
 
 	pdma->csr_ring =  devm_ioremap(&pdev->dev, res->start,
 				       resource_size(res));
-	if (IS_ERR(pdma->csr_ring)) {
+	if (!pdma->csr_ring) {
 		dev_err(&pdev->dev, "Failed to ioremap ring csr region");
-		return PTR_ERR(pdma->csr_ring);
+		return -ENOMEM;
 	}
 
 	/* Get DMA ring cmd csr region */
@@ -1923,9 +1923,9 @@
 
 	pdma->csr_ring_cmd = devm_ioremap(&pdev->dev, res->start,
 					  resource_size(res));
-	if (IS_ERR(pdma->csr_ring_cmd)) {
+	if (!pdma->csr_ring_cmd) {
 		dev_err(&pdev->dev, "Failed to ioremap ring cmd csr region");
-		return PTR_ERR(pdma->csr_ring_cmd);
+		return -ENOMEM;
 	}
 
 	/* Get efuse csr region */
@@ -1937,9 +1937,9 @@
 
 	pdma->csr_efuse = devm_ioremap(&pdev->dev, res->start,
 				       resource_size(res));
-	if (IS_ERR(pdma->csr_efuse)) {
+	if (!pdma->csr_efuse) {
 		dev_err(&pdev->dev, "Failed to ioremap efuse csr region");
-		return PTR_ERR(pdma->csr_efuse);
+		return -ENOMEM;
 	}
 
 	/* Get DMA error interrupt */