rtc: brcmstb-waketimer: switch to rtc_time64_to_tm

Call the 64bit version of rtc_time_to_tm as the range is enforced by the
core.
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-brcmstb-waketimer.c

@@ -132,7 +132,7 @@ static int brcmstb_waketmr_gettime(struct device *dev,
 
 	wktmr_read(timer, &now);
 
-	rtc_time_to_tm(now.sec, tm);
+	rtc_time64_to_tm(now.sec, tm);
 
 	return 0;
 }