rtc: stop validating rtc_time after rtc_time_to_tm

rtc_time_to_tm never generates an invalid tm. It is not necessary to
validate it.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
diff --git a/drivers/rtc/rtc-starfire.c b/drivers/rtc/rtc-starfire.c
index 7fc3697..a7d4932 100644
--- a/drivers/rtc/rtc-starfire.c
+++ b/drivers/rtc/rtc-starfire.c
@@ -28,7 +28,7 @@ static u32 starfire_get_time(void)
 static int starfire_read_time(struct device *dev, struct rtc_time *tm)
 {
 	rtc_time_to_tm(starfire_get_time(), tm);
-	return rtc_valid_tm(tm);
+	return 0;
 }
 
 static const struct rtc_class_ops starfire_rtc_ops = {