rtc-cmos: convert RTC_AIE/RTC_UIE to rtc irq API

Drop ioctl function that handles RTC_AIE/RTC_UIE, and use instead the
rtc subsystem API (alarm_irq_enable/update_irq_enable callbacks).

Signed-off-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>