powerpc/time: stop validating rtc_time in .read_time

The RTC core is always calling rtc_valid_tm after the read_time callback.
It is not necessary to call it just before returning from the callback.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/time.c

@@ -1234,7 +1234,7 @@ void calibrate_delay(void)
 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
 {
 	ppc_md.get_rtc_time(tm);
-	return rtc_valid_tm(tm);
+	return 0;
 }
 
 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)