pwm: brcmstb: Fix check of devm_ioremap_resource() return code

The change fixes potential oops while accessing iomem on invalid address
if devm_ioremap_resource() fails due to some reason.

The devm_ioremap_resource() function returns ERR_PTR() and never returns
NULL, which makes useless a following check for NULL.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Fixes: 3a9f5957020f ("pwm: Add Broadcom BCM7038 PWM controller support")
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-brcmstb.c

@@ -274,8 +274,8 @@ static int brcmstb_pwm_probe(struct platform_device *pdev)
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	p->base = devm_ioremap_resource(&pdev->dev, res);
-	if (!p->base) {
-		ret = -ENOMEM;
+	if (IS_ERR(p->base)) {
+		ret = PTR_ERR(p->base);
 		goto out_clk;
 	}