clk: meson-axg: fix return value check in axg_clkc_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: 78b4af31 ("clk: meson-axg: add clock controller drivers")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/meson/axg.c

@@ -880,7 +880,7 @@ static int axg_clkc_probe(struct platform_device *pdev)
 	/*  Generic clocks and PLLs */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	clk_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
-	if (IS_ERR(clk_base)) {
+	if (!clk_base) {
 		dev_err(&pdev->dev, "Unable to map clk base\n");
 		return -ENXIO;
 	}