drivers/rtc/rtc-cmos.c: work around bios clearing rtc control

The bios may clear the rtc control register when resuming the system. Since the
cmos interrupt handler may now be run before the rtc_cmos is resumed, this can
cause the interrupt handler to ignore an alarm since the alarm bit is not set in
the rtc control register. To work around this, check if the rtc_cmos is
suspended and use the stored value for the rtc control register.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
Reviewed-by: Sameer Nanda <snanda@chromium.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>