drivers/rtc: Replace PTR_RET with PTR_ERR_OR_ZERO

PTR_RET is now deprecated. Use PTR_ERR_OR_ZERO instead.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/rtc/rtc-pcf8583.c b/drivers/rtc/rtc-pcf8583.c
index 843a745..c263984 100644
--- a/drivers/rtc/rtc-pcf8583.c
+++ b/drivers/rtc/rtc-pcf8583.c
@@ -285,7 +285,7 @@
 				pcf8583_driver.driver.name,
 				&pcf8583_rtc_ops, THIS_MODULE);
 
-	return PTR_RET(pcf8583->rtc);
+	return PTR_ERR_OR_ZERO(pcf8583->rtc);
 }
 
 static const struct i2c_device_id pcf8583_id[] = {