rtc: sc27xx: Remove interrupts disable and clear in probe()

When registering one rtc device, it will check to see if there is an
alarm already set in rtc hardware by issuing __rtc_read_alarm(). So
we should not disable the RTC interrupts and clear the interrupts
status in probe() function.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>