staging: android-alarm: Add android alarm driver & in-kernel alarm interface

Drivers can now create alarms that will use an hrtimer while the
system is running and the rtc to wake up from suspend.

CC: Arve Hjønnevåg <arve@android.com>
CC: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
[Fold and move alarm driver and interface to staging,
 fix whitespace issue, drop kconfig & make file changes
 as it currently doesn't build  -jstultz]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>