RTC: Remove Kconfig symbol for UIE emulation

The effect of changing the value of this symbol is gone since 042620a0
(RTC: Remove UIE emulation).

Remove symbol too.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
LKML-Reference: <1295625406-15340-1-git-send-email-u.kleine-koenig@pengutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>