bus: arm-integrator-lm: Fix return value check in integrator_ap_lm_probe()

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

Link: https://lore.kernel.org/r/20200525091634.8274-1-linus.walleij@linaro.org
Fixes: ccea5e8a ("bus: Add driver for Integrator/AP logic modules")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20200520032150.165388-1-weiyongjun1@huawei.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/bus/arm-integrator-lm.c

@@ -78,10 +78,10 @@ static int integrator_ap_lm_probe(struct platform_device *pdev)
 
 	/* Look up the system controller */
 	syscon = of_find_matching_node(NULL, integrator_ap_syscon_match);
-	if (IS_ERR(syscon)) {
+	if (!syscon) {
 		dev_err(dev,
 			"could not find Integrator/AP system controller\n");
-		return PTR_ERR(syscon);
+		return -ENODEV;
 	}
 	map = syscon_node_to_regmap(syscon);
 	if (IS_ERR(map)) {