drivers/rtc/rtc-s3c.c: fix prototype for s3c_rtc_setaie()

Fix s3c_rtc_setaie() prototype to eliminate the following compile
warning:

  drivers/rtc/rtc-s3c.c:383: warning: initialization from incompatible pointer type

(akpm: the rtc_class_ops.alarm_irq_enable() handler is being passed two
arguments where it expects just one, presumably with undesired effects)

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>