spi: spi-fsl-qspi: Fix return value check of devm_ioremap() in probe

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

Fixes: 858e26a5 ("spi: spi-fsl-qspi: Reduce devm_ioremap size to 4 times AHB buffer size")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Ashish Kumar <Ashish.Kumar@nxp.com>
Acked-by: Han Xu <han.xu@nxp.com>
Link: https://lore.kernel.org/r/20200422014543.111070-1-weiyongjun1@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-qspi.c

@@ -880,8 +880,8 @@ static int fsl_qspi_probe(struct platform_device *pdev)
 	/* Since there are 4 cs, map size required is 4 times ahb_buf_size */
 	q->ahb_addr = devm_ioremap(dev, q->memmap_phy,
 				   (q->devtype_data->ahb_buf_size * 4));
-	if (IS_ERR(q->ahb_addr)) {
-		ret = PTR_ERR(q->ahb_addr);
+	if (!q->ahb_addr) {
+		ret = -ENOMEM;
 		goto err_put_ctrl;
 	}