rtc: stop validating rtc_time after rtc_time64_to_tm

rtc_time64_to_tm never generates an invalid tm. It is not necessary to
validate it.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-ab3100.c

@@ -106,7 +106,7 @@ static int ab3100_rtc_read_time(struct device *dev, struct rtc_time *tm)
 
 	rtc_time64_to_tm(time, tm);
 
-	return rtc_valid_tm(tm);
+	return 0;
 }
 
 static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)

drivers/rtc/rtc-mc13xxx.c

@@ -85,7 +85,7 @@ static int mc13xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
 
 	rtc_time64_to_tm((time64_t)days1 * SEC_PER_DAY + seconds, tm);
 
-	return rtc_valid_tm(tm);
+	return 0;
 }
 
 static int mc13xxx_rtc_set_mmss(struct device *dev, time64_t secs)

drivers/rtc/rtc-zynqmp.c

@@ -122,7 +122,7 @@ static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
 		rtc_time64_to_tm(read_time, tm);
 	}
 
-	return rtc_valid_tm(tm);
+	return 0;
 }
 
 static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)