watchdog: bcm_kona_wdt: Use correct return value for bcm_kona_wdt_probe()

When call function devm_platform_ioremap_resource(), we should use IS_ERR()
to check the return value and return PTR_ERR() if failed.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1590391864-308-1-git-send-email-yangtiezhu@loongson.cnSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/bcm_kona_wdt.c

@@ -279,7 +279,7 @@ static int bcm_kona_wdt_probe(struct platform_device *pdev)
 
 	wdt->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(wdt->base))
-		return -ENODEV;
+		return PTR_ERR(wdt->base);
 
 	wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
 	ret = bcm_kona_wdt_set_resolution_reg(wdt);