staging: android-alarm: Fix namespace collision with upstreamed alarmtimers

The upstreamed alarmtimers are similar but not quite 100% API
compatibile with the android in-kernel alarm api. To aid the
transition, prefix the the android in-kernel api with android_

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>
Change-Id: I0efc1d236b5c6e22b7d3801774f2c1402e2c021e