ASoC: SOF: imx8: Fix return value check in imx8_probe()

In case of error, the function devm_ioremap_wc() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check should be
replaced with NULL test.

Fixes: 202acc56 ("ASoC: SOF: imx: Add i.MX8 HW support")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Link: https://lore.kernel.org/r/20190826120003.183279-1-weiyongjun1@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/imx/imx8.c

@@ -296,10 +296,10 @@ static int imx8_probe(struct snd_sof_dev *sdev)
 	sdev->bar[SOF_FW_BLK_TYPE_SRAM] = devm_ioremap_wc(sdev->dev, res.start,
 							  res.end - res.start +
 							  1);
-	if (IS_ERR(sdev->bar[SOF_FW_BLK_TYPE_SRAM])) {
+	if (!sdev->bar[SOF_FW_BLK_TYPE_SRAM]) {
 		dev_err(sdev->dev, "failed to ioremap mem 0x%x size 0x%x\n",
 			base, size);
-		ret = PTR_ERR(sdev->bar[SOF_FW_BLK_TYPE_SRAM]);
+		ret = -ENOMEM;
 		goto exit_pdev_unregister;
 	}
 	sdev->mailbox_bar = SOF_FW_BLK_TYPE_SRAM;