RTC: Clean out UIE icotl implementations

With the generic RTC rework, the UIE mode irqs are handled
in the generic layer, and only hardware specific ioctls
get passed down to the rtc driver layer.

So this patch removes the UIE mode ioctl handling in the rtc
driver layer, which never get used.

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>