android-alarm: Remove unused android alarm in-kernel interfaces

Now that alarm-dev.c uses the upstreamed alarmtimer interfaces,
we can remove the otherwise unused in-kernel android alarm api.

CC: Colin Cross <ccross@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Android Kernel Team <kernel-team@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>