rtc: don't use flush_scheduled_work()

flush_scheduled_work() is deprecated and scheduled to be removed.  On
removal, directly cancel the work, and flush the uie_task in
rtc-dev.c::clear_uie().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: rtc-linux@googlegroups.com
diff --git a/drivers/rtc/rtc-ds1305.c b/drivers/rtc/rtc-ds1305.c
index 48da85e..077af1d 100644
--- a/drivers/rtc/rtc-ds1305.c
+++ b/drivers/rtc/rtc-ds1305.c
@@ -813,7 +813,7 @@
 	if (spi->irq) {
 		set_bit(FLAG_EXITING, &ds1305->flags);
 		free_irq(spi->irq, ds1305);
-		flush_scheduled_work();
+		cancel_work_sync(&ds1305->work);
 	}
 
 	rtc_device_unregister(ds1305->rtc);