RTC: Cleanup rtc_class_ops->update_irq_enable()

Now that the generic code handles UIE mode irqs via periodic
alarm interrupts, no one calls the
rtc_class_ops->update_irq_enable() method anymore.

This patch removes the driver hooks and implementations of
update_irq_enable if no one else is calling it.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
CC: rtc-linux@googlegroups.com
Signed-off-by: John Stultz <john.stultz@linaro.org>

drivers/rtc/rtc-mc13xxx.c

@@ -282,12 +282,6 @@ static irqreturn_t mc13xxx_rtc_update_handler(int irq, void *dev)
 	return IRQ_HANDLED;
 }
 
-static int mc13xxx_rtc_update_irq_enable(struct device *dev,
-		unsigned int enabled)
-{
-	return mc13xxx_rtc_irq_enable(dev, enabled, MC13XXX_IRQ_1HZ);
-}
-
 static int mc13xxx_rtc_alarm_irq_enable(struct device *dev,
 		unsigned int enabled)
 {
@@ -300,7 +294,6 @@ static const struct rtc_class_ops mc13xxx_rtc_ops = {
 	.read_alarm = mc13xxx_rtc_read_alarm,
 	.set_alarm = mc13xxx_rtc_set_alarm,
 	.alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
-	.update_irq_enable = mc13xxx_rtc_update_irq_enable,
 };
 
 static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)