audiopolicy: engine: anticipate usage deprecation

USAGE_NOTIFICATION_COMMUNICATION_<INSTANT|DELAYED|REQUEST> will be deprecated
in android T. USAGE_NOTIFICATION_EVENT will be kept and audio hal visible
(removing the issue of convertion if AUDIO_NO_SYSTEM_DECLARATIONS is set.

This CL removes the deprecated usage in hardcoded and XML configuration of
audio policy engine.

Signed-off-by: Francois Gaffie <francois.gaffie@renault.com>
Change-Id: I6a2d581357d71662800f0059fa501f6752247867