staging: Remove the Android alarm-dev driver

The functionality provided by the Android alarm-dev driver
should now be present in the timerfd interface (thanks to
Greg Hackmann and Todd Poynor).

As of Lollipop, AOSP can make use of the timerfd if
alarm-dev is not present (though a fixup for setting the
rtc time if rtc0 isn't the backing for _ALARM clockids has
been applied post-Lollipop).

Thus, we should be able to remove alarm-dev from staging.

Cc: Greg Hackmann <ghackmann@google.com>
Cc: Elliott Hughes <enh@google.com>
Cc: Todd Poynor <toddpoynor@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Mark Salyzyn <salyzyn@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Change-Id: Ia905d4b809cc1614ddde01ccb791fc56ac292fa7