drivers/rtc/rtc-pcf2127.c: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO

Fix a coccinelle error regarding usage of IS_ERR and PTR_ERR instead of
PTR_ERR_OR_ZERO.
Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-pcf2127.c

@@ -197,10 +197,7 @@ static int pcf2127_probe(struct i2c_client *client,
 				pcf2127_driver.driver.name,
 				&pcf2127_rtc_ops, THIS_MODULE);
 
-	if (IS_ERR(pcf2127->rtc))
-		return PTR_ERR(pcf2127->rtc);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(pcf2127->rtc);
 }
 
 static const struct i2c_device_id pcf2127_id[] = {