watchdog: pic32-wdt: Fix return value check in pic32_wdt_drv_probe()

In case of error, the function devm_kzalloc() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check should
be replaced with NULL test.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/pic32-wdt.c

@@ -174,8 +174,8 @@ static int pic32_wdt_drv_probe(struct platform_device *pdev)
 	struct resource *mem;
 
 	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
-	if (IS_ERR(wdt))
-		return PTR_ERR(wdt);
+	if (!wdt)
+		return -ENOMEM;
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	wdt->regs = devm_ioremap_resource(&pdev->dev, mem);