drivers/rtc/rtc-ds3232.c: add alarm function

The DS3232 RTC driver only has the tick function.  Add an alarm function
so the driver is complete.

Signed-off-by: Lan Chunhe-B25806 <b25806@freescale.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 636ba82..6a77437 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -171,7 +171,8 @@
 	depends on RTC_CLASS && I2C
 	help
 	  If you say yes here you get support for Dallas Semiconductor
-	  DS3232 real-time clock chips.
+	  DS3232 real-time clock chips. If an interrupt is associated
+	  with the device, the alarm functionality is supported.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called rtc-ds3232.