staging: android-alarm: Reenable android alarm driver

Now that it builds, re-enable android alarm driver in
the makefile and kconfig

CC: Arve Hjønnevåg <arve@android.com>
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>