rtc: alarm: Add power-on alarm feature

Android does not support powering up of phone through alarm.
Adding shutdown hook in alarm driver which will set alarm while phone
is going down so as to power-up the phone after alarm expiration.

CRs-Fixed: 432312
Change-Id: I21786d264b93f7c0c660823a0a1a221c1b4df7b2
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>
rtc: alarm: Set power-on alarm 120 sec before actual alarm time

This will add extra buffer time for booting-up the device before
actual alarm expiration time.

Change-Id: I02cad84c394a6aab943fff37a1a0de56bb511f56
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>

Conflicts:
	drivers/rtc/alarm.c
kernel: alarm: fix the BUG that device automatically powers on

The value of alarm.time is invalid if we get it by:
    memset(&alarm, 0, sizeof(alarm)).
So function of rtc_set_alarm aborts before it really calls into:
    rtc->ops->set_alarm.
Then we can`t disable the RTC alarm by that. The result is some
alarms enabled by alarm_suspend are not disabled correctly during
alarm_resume. And device will automatically power on.

CRs-fixed: 524051
Change-Id: Ibc99e62878d17ad4f50325630bf0862207e2cf3f
Signed-off-by: Figo Wang <figow@codeaurora.org>
kernel: alarm: add dedicated alarm type for poweroff alarm

Now we use type of RTC_WAKEUP for the poweroff alarm.
Actually lots of other applications also use this type.
But these applications never expect the device will
power on after it has been shut down. So we need to
add dedicated alarm type for the Deskclock or similar
applications.

CRs-fixed: 529674
Change-Id: I9b7911906446daa1aeb5835478c9837f8ef797f2
Signed-off-by: Figo Wang <figow@codeaurora.org>
kernel: alarm: Do not call rtc_alarm_irq_enable in IRQ Disabled context

Currently shutdown hook of alarm driver is calling
the rtc_alarm_irq_enable API in interrupts disabled
context. So fix the alarm_shutdown function to call
in API rtc_alarm_irq_enable in interrupt enabled context.

CRs-Fixed: 591790
Change-Id: Iebd82482be1dc95c6c978b617e1c18eb36e1b6eb
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>