mailbox: zynqmp-ipi: Fix NULL vs IS_ERR() check in zynqmp_ipi_mbox_probe()

In case of error, the function devm_ioremap() returns NULL pointer not
ERR_PTR(). So we should check whether the return value of devm_ioremap()
is NULL instead of IS_ERR.

Fixes: 4981b82b ("mailbox: ZynqMP IPI mailbox controller")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/zynqmp-ipi-mailbox.c

@@ -504,10 +504,9 @@ static int zynqmp_ipi_mbox_probe(struct zynqmp_ipi_mbox *ipi_mbox,
 		mchan->req_buf_size = resource_size(&res);
 		mchan->req_buf = devm_ioremap(mdev, res.start,
 					      mchan->req_buf_size);
-		if (IS_ERR(mchan->req_buf)) {
+		if (!mchan->req_buf) {
 			dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
-			ret = PTR_ERR(mchan->req_buf);
-			return ret;
+			return -ENOMEM;
 		}
 	} else if (ret != -ENODEV) {
 		dev_err(mdev, "Unmatched resource %s, %d.\n", name, ret);
@@ -520,10 +519,9 @@ static int zynqmp_ipi_mbox_probe(struct zynqmp_ipi_mbox *ipi_mbox,
 		mchan->resp_buf_size = resource_size(&res);
 		mchan->resp_buf = devm_ioremap(mdev, res.start,
 					       mchan->resp_buf_size);
-		if (IS_ERR(mchan->resp_buf)) {
+		if (!mchan->resp_buf) {
 			dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
-			ret = PTR_ERR(mchan->resp_buf);
-			return ret;
+			return -ENOMEM;
 		}
 	} else if (ret != -ENODEV) {
 		dev_err(mdev, "Unmatched resource %s.\n", name);
@@ -543,10 +541,9 @@ static int zynqmp_ipi_mbox_probe(struct zynqmp_ipi_mbox *ipi_mbox,
 		mchan->req_buf_size = resource_size(&res);
 		mchan->req_buf = devm_ioremap(mdev, res.start,
 					      mchan->req_buf_size);
-		if (IS_ERR(mchan->req_buf)) {
+		if (!mchan->req_buf) {
 			dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
-			ret = PTR_ERR(mchan->req_buf);
-			return ret;
+			return -ENOMEM;
 		}
 	} else if (ret != -ENODEV) {
 		dev_err(mdev, "Unmatched resource %s.\n", name);
@@ -559,10 +556,9 @@ static int zynqmp_ipi_mbox_probe(struct zynqmp_ipi_mbox *ipi_mbox,
 		mchan->resp_buf_size = resource_size(&res);
 		mchan->resp_buf = devm_ioremap(mdev, res.start,
 					       mchan->resp_buf_size);
-		if (IS_ERR(mchan->resp_buf)) {
+		if (!mchan->resp_buf) {
 			dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
-			ret = PTR_ERR(mchan->resp_buf);
-			return ret;
+			return -ENOMEM;
 		}
 	} else if (ret != -ENODEV) {
 		dev_err(mdev, "Unmatched resource %s.\n", name);